Campylobacter jejuni Induces Secretion of Proinflammatory Chemokines from Human Intestinal Epithelial Cells
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感染与免疫杂志 2005年第7期
Naval Medical Research Center, Silver Spring, Maryland
ABSTRACT
Campylobacter jejuni is a common cause of diarrhea in humans. While the pathogenic mechanisms of C. jejuni are not completely understood, host inflammatory responses are thought to be contributing factors. In this report, C. jejuni 81-176 is shown to up-regulate chemokines essential to inflammatory responses. Growth-related oncogene (GRO), GRO, macrophage inflammatory protein 1, monocyte chemoattractant protein 1 (MCP-1), and gamma interferon-inducible protein 10 (IP-10) mRNA transcription in INT-407 cells was enhanced within 4 h of bacterial exposure. Infection with viable campylobacters was necessary for sustained chemokine transcription and was NF-B dependent. GRO, IP-10, and MCP-1 chemokine secretions were confirmed by immunological assays.
TEXT
Campylobacters are a leading cause of diarrheal disease worldwide (2), yet very little is known about bacterial pathogenesis or bacterium-host interactions. Inflammation of the colon is a hallmark of campylobacter infections, and leukocytes and erythrocytes are almost always found in stool during active illness (13). Inflammation is thought to mediate, at least in part, host injury (1).
Intestinal epithelial cells constitute one of the first physical barriers to enteric pathogens and likely initiate the host response. In response to injury, epithelial cells secrete cellular factors that are capable of recruiting macrophages and other cellular components of the immune and inflammatory responses (6). During campylobacter infections, mononuclear phagocytes infiltrate the submucosal lining as a consequence of tissue injury (12). Additionally, human epithelial and monocytic cell lines liberate potent proinflammatory cytokines (interleukin-6 and interleukin-8) in response to Campylobacter jejuni exposure in vitro (4, 5). We demonstrate here that epithelial cells transcribe and secrete other key chemokines essential to the activation of the host's inflammatory response when exposed to C. jejuni 81-176 (4).
GRO gene transcription. The growth-related oncogene (GRO), GRO, and GRO chemokines are potent neutrophil chemoattractants produced by epithelial cells and a variety of other cell types (9, 10, 14). Expression of mRNA for these factors was assessed via reverse transcriptase (RT) PCR at 2, 4, and 24 h following infection of INT-407 cells with 81-176 (Fig. 1, lanes 2, 5, and 8). GRO message was slightly upregulated compared to uninfected controls at 2 and 4 h (Fig. 1, lanes 2 and 5). By 24 h, however, GRO mRNA transcription by cells cocultured with 81-176 was markedly enhanced compared to control cultures (lane 8). GRO message was readily detectable in 81-176-inoculated culture wells at 2 and 4 h but was most prominent 24 h after infection (Fig. 1, lanes 2, 5, and 8). Epithelial cells cultured with tumor necrosis factor alpha (TNF-) (20 ng/ml) served as positive controls for this assay and subsequent assays. GRO message was not up-regulated by either 81-176 or TNF- exposure but was detected in both uninoculated cultures and those cultured with campylobacters (Fig. 1, row 2).
Secretion of GRO by intestinal epithelial cells. The concentrations of GRO in supernatants of INT-407 cells were evaluated through enzyme-linked immunosorbent assay (ELISA) at 4 and 24 h after infection (Fig. 2A). Supernatants from 81-176-inoculated cultures demonstrated a slight increase in GRO levels (means ± standard deviations) compared to uninoculated culture wells as early as 4 h postinoculation (49 ± 76 pg/ml). However by the 24-hour time point, epithelial cells cocultured with 81-176 secreted 670 ± 81 pg/ml GRO (P 0.001). TNF-supplemented cultures secreted 1,134 ± 163 pg/ml GRO at 4 h and 1,261 ± 284 at 24 h (P < 0.001). Chemokine levels detected in uninoculated controls were negligible at this time point (17 ± 30 pg/ml).
Transcription of MCP-1 and MIP-1 message. Monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein 1 (MIP-1) are essential components of the immune response to enteric pathogens (3, 15). MCP-1 is a monocyte/basophil chemoattractant and activating factor produced by epithelial cells in response to physical assaults (7, 14). MIP-1, a chemoattractant for B cells, eosinophils, and killer T cells, is produced by a variety of cell types (15). Within 2 hours of inoculation, MCP-1 message in tissue culture exposed to 81-176 was up-regulated. Substantial levels of MCP-1 message were detected in these cells by 24 h (Fig. 1, lanes 2, 5, and 8). MIP-1 message detected in 81-176-inoculated cultures remained at levels similar to those found in uninoculated control cultures, with only a slight up-regulation detected at 24 h (Fig. 1, lane 8). The TNF--treated cultures also demonstrated moderate induction of MIP-1 message compared to uninoculated cultures (Fig. 1, lane 9).
Secretion of MCP-1. The production of MCP-1 by epithelial cells was evaluated by ELISA at 4 and 24 h (Fig. 2B). INT-407 cells inoculated with 81-176 secreted moderate amounts of MCP-1 at 4 h. Supernatants from cells cultured with 81-176 produced 128 ± 43 pg/ml MCP-1, compared to 6.2 ± 10 pg/ml detected in uninoculated cultures (P 0.01). By 24 h, 793 ± 174 pg/ml MCP-1 was detected in 81-176-inoculated cultures, compared to 141 ± 68 pg/ml found in controls (P 0.003).
Expression of interferon-inducible protein (IP-10). Gamma interferon-inducible protein IP-10 is a monocyte and T-lymphocyte chemoattractant and is frequently present in inflamed tissue (11, 15). IP-10 message in INT-407 cells cocultured with 81-176 was up-regulated. Within 4 h of exposure to campylobacters, message was strongly up-regulated compared to that in uninoculated control wells, and levels of IP-10 message remained elevated through 24 h (Fig. 1, lanes 5 and 8). INT-407 cultures supplemented with 20 ng/ml TNF- up-regulated IP-10 message within 4 h, and message remained elevated through 24 h, similar to results seen with 81-176-inoculated cultures (Fig. 1, lanes 6 and 9).
IP-10 protein was detectable by ELISA in 24-hour cultures (Fig. 2C). Supernatants from 24-hour INT-407 cells cultured with 81-176 contained 1,356 ± 204 pg/ml IP-10 (P 0.0004). Normal or media control cultures produced negligible amounts of the cytokine (35 ± 61 pg/ml). TNF--supplemented cultures produced 1,862 ± 276 pg/ml of the chemokine by 24 h (P 0.0004). At the earlier time point, there was no statistically significant difference in chemokine levels of 81-176 and TNF- cultures compared to normal control cultures; P values were 0.98 and 0.493, respectively.
Viable campylobacters are required for sustained chemokine mRNA transcription. INT-407 monolayers were inoculated with 81-176, either viable or heat killed, at a multiplicity of infection of 100 bacteria to each epithelial cell. Heat-killed 81-176 was incubated at 70°C for 30 min and then plated to verify the absence of viability. To control for the effects of bacterial lipooligosaccharide (LOS)/lipopolysaccharide (LPS) on chemokine transcription, Escherichia coli LPS (Sigma Chemical Co., St. Louis, MO) was included in the assay at 50 μg/ml. Chemokine message was assayed at 4 and 24 h. Sustained GRO, MCP-1, MIP-1, and IP-10 transcription required viable campylobacters or heat-sensitive bacterial products. Heat-killed 81-176 mediated a moderate and short-lived transcription of GRO and MCP-1 genes that were detectable at 4 h but waned by the later time point compared to uninoculated control cultures (Fig. 3, lanes 1, 4, 5, and 8). A moderate MIP-1 response was also detected at 4 and 24 h (Fig. 3, lanes 4 and 8). With the exception of GRO transcription, similar responses were observed in cultures incubated with E. coli LPS (Fig. 3, lanes 3 and 7). E. coli LPS induced GRO transcription as late as 24 h, a response not detected when epithelial cells were inoculated with heat-killed campylobacters (Fig. 3, lane 7 and 8). Viable campylobacters induced marked transcription of each chemokine gene by 24 h (Fig. 3, lanes 2 and 6). These data indicate that viable 81-176 or possibly heat-sensitive or synthesized bacterial products other than LOS are required for inflammatory chemokine production by human epithelial cells.
Requirement of NF-B activation for chemokine transcription. The requirement of transcription factor NF-B activation for chemokine mRNA synthesis was evaluated through inhibition studies. Intestinal epithelial cells were preincubated with caffeic acid phenethyl ester (CAPE) (Sigma Chemical Co., St. Louis, Mo.) at 50 μM (8) for 1 h prior to inoculation with viable 81-176 at a multiplicity of infection of 100:1. CAPE is a potent and specific inhibitor of NF-B activation and is known for its immunomodulatory and anti-inflammatory effects on a range of eukaryotic cell types (8). Preincubation of epithelial cells with CAPE prevented transcription of IP-10 message at 4 and 24 h (Fig. 4, lanes 3 and 6). Inhibition of NF-B activation also greatly reduced MCP-1 and MIP-1 transcription at both time points. These data suggest that transcription of the genes examined proceeds, at least in part, through the activation of transcription factor NF-B. The incomplete inhibition of MCP-1 and MIP-1 might be due to the activity of compensatory transcription factors not affected by CAPE.
In summary, secretion of select chemokines by human intestinal epithelial cells exposed to campylobacters may provide the initial signals for acute inflammatory responses. We demonstrate that transcription of GRO, GRO, MCP-1, MIP-1, and IP-10 chemokine genes are up-regulated by human intestinal epithelial cells following exposure to viable 81-176 or bacterial products other than LOS. These transcriptional responses were apparently mediated by NF-B activation. We also demonstrate the secretion of GRO, MCP-1, and IP-10 proteins by ELISA. These chemokines are essential components of the inflammatory immune response to enteric pathogens, and additionally, these data provide insight into the mechanisms of tissue injury by campylobacters. These data further support the premise that inflammation plays a significant role in C. jejuni pathogenesis and that the intestinal epithelial tissue likely play significant roles in initiating the inflammatory response.
ACKNOWLEDGMENTS
This work was supported by Military Infectious Diseases Research Program Work Unit Number A30001-04-NM.
The opinions and assertions herein are the private ones of the authors and are not to be construed as official or reflecting the views of the Navy Department or the naval service at large.
Present address: Enterics and STD Laboratory, CBER, FDA, 29 Lincoln Drive, Room 424, Bethesda, MD 20892-4555.
REFERENCES
1. Blaser, M. J., R. B. Parsons, and W. L. Wang. 1980. Acute colitis caused by Campylobacter fetus ss. jejuni. Gastroenterology 78:448-453.
2. Coker, A. O., R. D. Isokpehi, B. N. Thomas, K. O. Amisu, and L. Obi. 2002. Human campylobacteriosis in developing countries. Emerg. Infect. Dis. 8:237-243.
3. Futagami, S., T. Hiratsuka, A. Tatsuguchi, K. Suzuki, M. Kusunoki, Y. Shinji, K. Shinoki, T. Iizumi, T. Akamatsu, H. Nishigaki, K. Wada, K. Miyake, K. Gudis, T. Tsukui, and C. Sakamoto. 2003. Monocyte chemoattractant protein 1 (MCP-1) released from Helicobacter pylori stimulated gastric epithelial cells induces cyclooxygenase 2 expression and activation in T cells. Gut 52:1257-1264.
4. Hickey, T. E., S. Baqar, A. L. Bourgeois, C. P. Ewing, and P. Guerry. 1999. Campylobacter jejuni stimulated secretion of interleukin-8 by INT407 cells. Infect. Immun. 67:88-93.
5. Joens, M. A., S. Totemeyer, D. J. Maskell, C. E. Bryant, and P. A. Barrow. 2003. Induction of proinflammatory responses in the human monocytic cell line THP-1 by Campylobacter jejuni. Infect. Immun. 71:2626-2633.
6. Jung, H. C., L. Eckmann, S. K. Yang, A. Panja, J. Fierer, E. Morzycka-Wroblewska, M. F. Kagnoff. 1995. A distinct array of proinflammatory cytokines is expressed in human colon epithelial cells in response to bacterial invasion. J. Clin. Investig. 95:55-65.
7. MacDermott, R. P. 1999. Chemokines in the inflammatory bowel diseases. J. Clin. Immunol. 19:266-272.
8. Natarajan, K., S. Singh, T. R. Burke, Jr., D. Grunberger, and B. B. Aggarwal. 1996. Caffeic acid phenethyl ester is a potent and specific inhibitor of nuclear transcription factor NF-kappa B. Proc. Natl. Acad. Sci. USA 93:9090-9095.
9. Sieveking, D., H. M. Mitchell, and A. S. Day. 2004. Gastric epithelial cell CXC chemokine secretion following Helicobacter pylori infection in vitro. J. Gastroenterol. Hepatol. 19:982-987.
10. Thorpe, C. M., W. E. Smith, B. P. Hurley, and D. W. K. Acheson. 2001. Shiga toxins induce, superinduce, and stabilize a variety of C-X-C chemokine mRNAs in intestinal epithelial cells, resulting in increased chemokine expression. Infect. Immun. 69:6140-6147.
11. Uguccioni, M., P. Gionchetti, D. F. Robbiani, F. Rizzello, S. Peruzzo, M. Campieri, and M. Baggiolini. 1999. Increased expression of IP-10, IL-8, MCP-1, and MCP-3 in ulcerative colitis. Am. J. Pathol. 155:331-336.
12. van Spreeuwel, J. P., G. C. Duursma, C. J. L. M. Meijer, R. Bax, P. C. M. Rosekrans, and J. Lindeman. 1985. Campylobacter colitis: histological, immunohistochemical and ultrastructural findings. Gut 26:945-951.
13. Wassenaar, T. M., and M. J. Blaser. 1999. Pathophysiology of Campylobacter jejuni infections of humans. Microbes Infect. 1:1023-1033.
14. Yamaoka, Y., M. Kita, T. Kodama, N. Sawai, T. Tanahashi, K. Kashima, and J. Imanishi. 1998. Chemokines in the gastric mucosa in Helicobacter pylori infection. Gut 42:609-617.
15. Yang, S. K., L. Eckmann, A. Panja, and M. F. Kagnoff. 1997. Differential and regulated expression of C-X-C, C-C, and C-chemokines by human colon epithelial cells. Gastroenterology 113:1214-1223.(Lan Hu and Thomas E. Hick)
ABSTRACT
Campylobacter jejuni is a common cause of diarrhea in humans. While the pathogenic mechanisms of C. jejuni are not completely understood, host inflammatory responses are thought to be contributing factors. In this report, C. jejuni 81-176 is shown to up-regulate chemokines essential to inflammatory responses. Growth-related oncogene (GRO), GRO, macrophage inflammatory protein 1, monocyte chemoattractant protein 1 (MCP-1), and gamma interferon-inducible protein 10 (IP-10) mRNA transcription in INT-407 cells was enhanced within 4 h of bacterial exposure. Infection with viable campylobacters was necessary for sustained chemokine transcription and was NF-B dependent. GRO, IP-10, and MCP-1 chemokine secretions were confirmed by immunological assays.
TEXT
Campylobacters are a leading cause of diarrheal disease worldwide (2), yet very little is known about bacterial pathogenesis or bacterium-host interactions. Inflammation of the colon is a hallmark of campylobacter infections, and leukocytes and erythrocytes are almost always found in stool during active illness (13). Inflammation is thought to mediate, at least in part, host injury (1).
Intestinal epithelial cells constitute one of the first physical barriers to enteric pathogens and likely initiate the host response. In response to injury, epithelial cells secrete cellular factors that are capable of recruiting macrophages and other cellular components of the immune and inflammatory responses (6). During campylobacter infections, mononuclear phagocytes infiltrate the submucosal lining as a consequence of tissue injury (12). Additionally, human epithelial and monocytic cell lines liberate potent proinflammatory cytokines (interleukin-6 and interleukin-8) in response to Campylobacter jejuni exposure in vitro (4, 5). We demonstrate here that epithelial cells transcribe and secrete other key chemokines essential to the activation of the host's inflammatory response when exposed to C. jejuni 81-176 (4).
GRO gene transcription. The growth-related oncogene (GRO), GRO, and GRO chemokines are potent neutrophil chemoattractants produced by epithelial cells and a variety of other cell types (9, 10, 14). Expression of mRNA for these factors was assessed via reverse transcriptase (RT) PCR at 2, 4, and 24 h following infection of INT-407 cells with 81-176 (Fig. 1, lanes 2, 5, and 8). GRO message was slightly upregulated compared to uninfected controls at 2 and 4 h (Fig. 1, lanes 2 and 5). By 24 h, however, GRO mRNA transcription by cells cocultured with 81-176 was markedly enhanced compared to control cultures (lane 8). GRO message was readily detectable in 81-176-inoculated culture wells at 2 and 4 h but was most prominent 24 h after infection (Fig. 1, lanes 2, 5, and 8). Epithelial cells cultured with tumor necrosis factor alpha (TNF-) (20 ng/ml) served as positive controls for this assay and subsequent assays. GRO message was not up-regulated by either 81-176 or TNF- exposure but was detected in both uninoculated cultures and those cultured with campylobacters (Fig. 1, row 2).
Secretion of GRO by intestinal epithelial cells. The concentrations of GRO in supernatants of INT-407 cells were evaluated through enzyme-linked immunosorbent assay (ELISA) at 4 and 24 h after infection (Fig. 2A). Supernatants from 81-176-inoculated cultures demonstrated a slight increase in GRO levels (means ± standard deviations) compared to uninoculated culture wells as early as 4 h postinoculation (49 ± 76 pg/ml). However by the 24-hour time point, epithelial cells cocultured with 81-176 secreted 670 ± 81 pg/ml GRO (P 0.001). TNF-supplemented cultures secreted 1,134 ± 163 pg/ml GRO at 4 h and 1,261 ± 284 at 24 h (P < 0.001). Chemokine levels detected in uninoculated controls were negligible at this time point (17 ± 30 pg/ml).
Transcription of MCP-1 and MIP-1 message. Monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein 1 (MIP-1) are essential components of the immune response to enteric pathogens (3, 15). MCP-1 is a monocyte/basophil chemoattractant and activating factor produced by epithelial cells in response to physical assaults (7, 14). MIP-1, a chemoattractant for B cells, eosinophils, and killer T cells, is produced by a variety of cell types (15). Within 2 hours of inoculation, MCP-1 message in tissue culture exposed to 81-176 was up-regulated. Substantial levels of MCP-1 message were detected in these cells by 24 h (Fig. 1, lanes 2, 5, and 8). MIP-1 message detected in 81-176-inoculated cultures remained at levels similar to those found in uninoculated control cultures, with only a slight up-regulation detected at 24 h (Fig. 1, lane 8). The TNF--treated cultures also demonstrated moderate induction of MIP-1 message compared to uninoculated cultures (Fig. 1, lane 9).
Secretion of MCP-1. The production of MCP-1 by epithelial cells was evaluated by ELISA at 4 and 24 h (Fig. 2B). INT-407 cells inoculated with 81-176 secreted moderate amounts of MCP-1 at 4 h. Supernatants from cells cultured with 81-176 produced 128 ± 43 pg/ml MCP-1, compared to 6.2 ± 10 pg/ml detected in uninoculated cultures (P 0.01). By 24 h, 793 ± 174 pg/ml MCP-1 was detected in 81-176-inoculated cultures, compared to 141 ± 68 pg/ml found in controls (P 0.003).
Expression of interferon-inducible protein (IP-10). Gamma interferon-inducible protein IP-10 is a monocyte and T-lymphocyte chemoattractant and is frequently present in inflamed tissue (11, 15). IP-10 message in INT-407 cells cocultured with 81-176 was up-regulated. Within 4 h of exposure to campylobacters, message was strongly up-regulated compared to that in uninoculated control wells, and levels of IP-10 message remained elevated through 24 h (Fig. 1, lanes 5 and 8). INT-407 cultures supplemented with 20 ng/ml TNF- up-regulated IP-10 message within 4 h, and message remained elevated through 24 h, similar to results seen with 81-176-inoculated cultures (Fig. 1, lanes 6 and 9).
IP-10 protein was detectable by ELISA in 24-hour cultures (Fig. 2C). Supernatants from 24-hour INT-407 cells cultured with 81-176 contained 1,356 ± 204 pg/ml IP-10 (P 0.0004). Normal or media control cultures produced negligible amounts of the cytokine (35 ± 61 pg/ml). TNF--supplemented cultures produced 1,862 ± 276 pg/ml of the chemokine by 24 h (P 0.0004). At the earlier time point, there was no statistically significant difference in chemokine levels of 81-176 and TNF- cultures compared to normal control cultures; P values were 0.98 and 0.493, respectively.
Viable campylobacters are required for sustained chemokine mRNA transcription. INT-407 monolayers were inoculated with 81-176, either viable or heat killed, at a multiplicity of infection of 100 bacteria to each epithelial cell. Heat-killed 81-176 was incubated at 70°C for 30 min and then plated to verify the absence of viability. To control for the effects of bacterial lipooligosaccharide (LOS)/lipopolysaccharide (LPS) on chemokine transcription, Escherichia coli LPS (Sigma Chemical Co., St. Louis, MO) was included in the assay at 50 μg/ml. Chemokine message was assayed at 4 and 24 h. Sustained GRO, MCP-1, MIP-1, and IP-10 transcription required viable campylobacters or heat-sensitive bacterial products. Heat-killed 81-176 mediated a moderate and short-lived transcription of GRO and MCP-1 genes that were detectable at 4 h but waned by the later time point compared to uninoculated control cultures (Fig. 3, lanes 1, 4, 5, and 8). A moderate MIP-1 response was also detected at 4 and 24 h (Fig. 3, lanes 4 and 8). With the exception of GRO transcription, similar responses were observed in cultures incubated with E. coli LPS (Fig. 3, lanes 3 and 7). E. coli LPS induced GRO transcription as late as 24 h, a response not detected when epithelial cells were inoculated with heat-killed campylobacters (Fig. 3, lane 7 and 8). Viable campylobacters induced marked transcription of each chemokine gene by 24 h (Fig. 3, lanes 2 and 6). These data indicate that viable 81-176 or possibly heat-sensitive or synthesized bacterial products other than LOS are required for inflammatory chemokine production by human epithelial cells.
Requirement of NF-B activation for chemokine transcription. The requirement of transcription factor NF-B activation for chemokine mRNA synthesis was evaluated through inhibition studies. Intestinal epithelial cells were preincubated with caffeic acid phenethyl ester (CAPE) (Sigma Chemical Co., St. Louis, Mo.) at 50 μM (8) for 1 h prior to inoculation with viable 81-176 at a multiplicity of infection of 100:1. CAPE is a potent and specific inhibitor of NF-B activation and is known for its immunomodulatory and anti-inflammatory effects on a range of eukaryotic cell types (8). Preincubation of epithelial cells with CAPE prevented transcription of IP-10 message at 4 and 24 h (Fig. 4, lanes 3 and 6). Inhibition of NF-B activation also greatly reduced MCP-1 and MIP-1 transcription at both time points. These data suggest that transcription of the genes examined proceeds, at least in part, through the activation of transcription factor NF-B. The incomplete inhibition of MCP-1 and MIP-1 might be due to the activity of compensatory transcription factors not affected by CAPE.
In summary, secretion of select chemokines by human intestinal epithelial cells exposed to campylobacters may provide the initial signals for acute inflammatory responses. We demonstrate that transcription of GRO, GRO, MCP-1, MIP-1, and IP-10 chemokine genes are up-regulated by human intestinal epithelial cells following exposure to viable 81-176 or bacterial products other than LOS. These transcriptional responses were apparently mediated by NF-B activation. We also demonstrate the secretion of GRO, MCP-1, and IP-10 proteins by ELISA. These chemokines are essential components of the inflammatory immune response to enteric pathogens, and additionally, these data provide insight into the mechanisms of tissue injury by campylobacters. These data further support the premise that inflammation plays a significant role in C. jejuni pathogenesis and that the intestinal epithelial tissue likely play significant roles in initiating the inflammatory response.
ACKNOWLEDGMENTS
This work was supported by Military Infectious Diseases Research Program Work Unit Number A30001-04-NM.
The opinions and assertions herein are the private ones of the authors and are not to be construed as official or reflecting the views of the Navy Department or the naval service at large.
Present address: Enterics and STD Laboratory, CBER, FDA, 29 Lincoln Drive, Room 424, Bethesda, MD 20892-4555.
REFERENCES
1. Blaser, M. J., R. B. Parsons, and W. L. Wang. 1980. Acute colitis caused by Campylobacter fetus ss. jejuni. Gastroenterology 78:448-453.
2. Coker, A. O., R. D. Isokpehi, B. N. Thomas, K. O. Amisu, and L. Obi. 2002. Human campylobacteriosis in developing countries. Emerg. Infect. Dis. 8:237-243.
3. Futagami, S., T. Hiratsuka, A. Tatsuguchi, K. Suzuki, M. Kusunoki, Y. Shinji, K. Shinoki, T. Iizumi, T. Akamatsu, H. Nishigaki, K. Wada, K. Miyake, K. Gudis, T. Tsukui, and C. Sakamoto. 2003. Monocyte chemoattractant protein 1 (MCP-1) released from Helicobacter pylori stimulated gastric epithelial cells induces cyclooxygenase 2 expression and activation in T cells. Gut 52:1257-1264.
4. Hickey, T. E., S. Baqar, A. L. Bourgeois, C. P. Ewing, and P. Guerry. 1999. Campylobacter jejuni stimulated secretion of interleukin-8 by INT407 cells. Infect. Immun. 67:88-93.
5. Joens, M. A., S. Totemeyer, D. J. Maskell, C. E. Bryant, and P. A. Barrow. 2003. Induction of proinflammatory responses in the human monocytic cell line THP-1 by Campylobacter jejuni. Infect. Immun. 71:2626-2633.
6. Jung, H. C., L. Eckmann, S. K. Yang, A. Panja, J. Fierer, E. Morzycka-Wroblewska, M. F. Kagnoff. 1995. A distinct array of proinflammatory cytokines is expressed in human colon epithelial cells in response to bacterial invasion. J. Clin. Investig. 95:55-65.
7. MacDermott, R. P. 1999. Chemokines in the inflammatory bowel diseases. J. Clin. Immunol. 19:266-272.
8. Natarajan, K., S. Singh, T. R. Burke, Jr., D. Grunberger, and B. B. Aggarwal. 1996. Caffeic acid phenethyl ester is a potent and specific inhibitor of nuclear transcription factor NF-kappa B. Proc. Natl. Acad. Sci. USA 93:9090-9095.
9. Sieveking, D., H. M. Mitchell, and A. S. Day. 2004. Gastric epithelial cell CXC chemokine secretion following Helicobacter pylori infection in vitro. J. Gastroenterol. Hepatol. 19:982-987.
10. Thorpe, C. M., W. E. Smith, B. P. Hurley, and D. W. K. Acheson. 2001. Shiga toxins induce, superinduce, and stabilize a variety of C-X-C chemokine mRNAs in intestinal epithelial cells, resulting in increased chemokine expression. Infect. Immun. 69:6140-6147.
11. Uguccioni, M., P. Gionchetti, D. F. Robbiani, F. Rizzello, S. Peruzzo, M. Campieri, and M. Baggiolini. 1999. Increased expression of IP-10, IL-8, MCP-1, and MCP-3 in ulcerative colitis. Am. J. Pathol. 155:331-336.
12. van Spreeuwel, J. P., G. C. Duursma, C. J. L. M. Meijer, R. Bax, P. C. M. Rosekrans, and J. Lindeman. 1985. Campylobacter colitis: histological, immunohistochemical and ultrastructural findings. Gut 26:945-951.
13. Wassenaar, T. M., and M. J. Blaser. 1999. Pathophysiology of Campylobacter jejuni infections of humans. Microbes Infect. 1:1023-1033.
14. Yamaoka, Y., M. Kita, T. Kodama, N. Sawai, T. Tanahashi, K. Kashima, and J. Imanishi. 1998. Chemokines in the gastric mucosa in Helicobacter pylori infection. Gut 42:609-617.
15. Yang, S. K., L. Eckmann, A. Panja, and M. F. Kagnoff. 1997. Differential and regulated expression of C-X-C, C-C, and C-chemokines by human colon epithelial cells. Gastroenterology 113:1214-1223.(Lan Hu and Thomas E. Hick)