Gupta Rm

PROTECTIVE OR PATHOGENIC IMMUNE RESPONSE TO GENITAL CHLAMYDIAL INFECTION IN WOMEN-A POSSIBLE ROLE OF CYTOKINE SECRETION PROFILE OF CERVICAL MUCOSAL CELLS

Little is known about genital mucosal immune response to chlamydial infection in women with or without sequelae (Chlamydia positive women with or without fertility disorders as infertility and multiple spontaneous abortions). Cervical lymphocytes were stimulated with chlamydial EBs and cytokine secretion was determined by ELISA, RT-PCR and ELISPOT assays. Stimulated cervical cells from women with fertility disorders (FD) secrete significantly (P<0.05) higher levels of IL-1beta, IL-6, IL-8 and IL-10 and cells from fertile women secrete significantly higher levels of IL-12 and IFN-gamma compared to other groups. RT-PCR analysis showed similar results for IFN-gamma and IL-12. For IL-10 and IL-4, mRNA expression levels were significantly higher (P<0.05) in cells obtained from women with FD compared to other groups. Results for ELISPOT assay were similar as those of RT-PCR. The results suggest that cytokine secretion profile of cervical cells may decide whether infection does not hamper fertility or will develop fertility disorder.

Higher incidence of persistent chronic infection of Chlamydia pneumoniae among coronary artery disease patients in India is a cause of concern

BackgroundThere is growing evidence that Chlamydia pneumoniae may be involved in the pathogenesis of atherosclerosis, as several studies have demonstrated the presence of the organism in atherosclerotic lesions. C. pneumoniae infections, which are especially persistent infections, have been difficult to diagnose either by serological methods or isolation of the organism from the tissue. Nucleic Acid Amplification tests (NAATs) has emerged as an important method for detecting C. pneumoniae. Inspite of high prevalence of C. pneumoniae specific antibodies in coronary heart disease patients, direct detection of C. pneumoniae in circulating blood of coronary artery disease (CAD) patients by sensitive nucleic acid amplification tests nested PCR (nPCR), multiplex PCR (mPCR) has not been carried out is required. Further correlation of the presence of C. pneumoniae in blood of CAD patients with C. pneumoniae specific IgA and IgG antibodies, which may indicative of the status of infection with the progression of atherosclerosis. This will help in order to prepare strategies for the antibiotic intervention to avoid the progression towards CAD.MethodsVenous blood was obtained from 91 CAD patients and 46 healthy controls. Nucleic acid amplification tests viz. nested -, semi-nested – and multiplex PCR were used for detection of C. pneumoniae. ELISA carried out prevalence of C. pneumoniae specific IgG and IgA antibodies.Results29.67% (27/91) patients were positive for C. pneumoniae using nested PCR. The sensitivity and specificity of semi-nested and multiplex PCR were 37.03%, 96.96% and 22.22%, 100% with respect to nested PCR. Positive nPCR patients were compared with presence of C. pneumoniae specific IgA, IgA+IgG and IgG antibodies. Among 27 (29.67%) nPCR C. pneumoniae positive CAD patients, 11(12%) were IgA positive, 13(14.2%) were IgA+IgG positive and only1 (1.1%) was IgG positive. A significant presence of C. pneumoniae was detected in heavy smokers, non-alcoholics and with family histories of diabetes and blood pressure group of CAD patients by nPCR.ConclusionThe results indicate synergistic association of C. pneumoniae infection and development of CAD with other risk factors. We also detected increased positivity for C. pneumoniae IgA than IgG in nPCR positive CAD patients. Positive nPCR findings in conjunction with persisting high C. pneumoniae specific antibody strongly suggest an ongoing infection.

Persistently Elevated Level of IL-8 in Chlamydia trachomatis Infected HeLa 229 Cells is Dependent on Intracellular Available Iron

Chlamydia trachomatis is a leading cause of sexually transmitted infection worldwide and responsible for myriad of immunopathological changes associated with reproductive health. Delayed secretion of proinflammatory chemokine interleukin (IL)-8 is a hallmark of chlamydial infection and is dependent on chlamydial growth. We examined the effect of iron chelators on IL-8 production in HeLa 229 (cervix epitheloid cell, CCL2) cells infected with C. trachomatis. IL-8 production was induced by Iron chelator DFO and Mimosine, however, synergy with chlamydial infection was obtained with DFO only. Temporal expression of proinflammatory secreted cytokines IL-1beta, TNF-alpha, and IL-8 did not show synchrony in Chlamydia trachomatis infected cells. Secretion of IL-8 from Hela cells infected with C. trachomatis was not dependent on IL-1 beta and TNF- alpha induction. These results indicate towards involvement of iron in chlamydia induced IL-8 production.

Serovar-specific immune responses to peptides of variable regions of Chlamydia trachomatis major outer membrane protein in serovar D-infected women

The role of major outer membrane protein (MOMP) variable regions in the interaction of chlamydiae and host cells has been evaluated and their role in neutralization of antibodies has been clearly demonstrated. There are also studies that delineate the contribution of these regions to the cell-mediated immune response of the host and suggest that serovar E elicits serovar-specific immune responses in infected humans. However, further studies with other serovars are required to confirm these findings and to elucidate the role and importance of serovar-specific responses of variable regions of MOMP in other serovars. We, therefore, performed a detailed analysis of the humoral and cellular immune responses against the serovar D-specific variable segments (VS) of MOMP in women infected with Chlamydia trachomatis. We found that VS4 elicits significantly higher responses (both humoral and cellular) than other VS peptides (VS1, VS2 and VS3). VS4 elicited significantly higher (Pxa0<xa00.0001) proliferative responses, interferon-gamma levels (Pxa0<xa00.0001) as well as higher prevalence (Pxa0<xa00.0001) of IgG antibodies against VS4 in serovar D-infected patients as compared to patients infected with other serovars, suggesting its role in serovar-specific immune responses.

Ferritin heavy chain-mediated iron homoeostasis regulates expression of IL-10 in Chlamydia trachomatis-infected HeLa cells

Chlamydia trachomatis is the leading cause of sexually transmitted infection worldwide, in which disease outcome is determined by the balance between pro‐ and anti‐inflammatory host immune responses. Iron plays important roles in regulation and enhancement of various pro‐ and anti‐inflammatory cytokines. Earlier studies have established essentiality of iron in C. trachomatis infection; however, there is lack of study wherein modulatory effect of iron regulated protein [FHC (ferritin heavy chain)] in regulation of anti‐inflammatory cytokine IL (interleukin)‐10 has been investigated. In this study, immunoblotting results showed the up‐regulation of FHC in C. trachomatis‐infected HeLa cells in comparison with mock (in vitro control). Further secretory IL‐10 level was significantly increased (P<0.001) or decreased (P<0.001) in response to iron supplementation [FAC (ferric ammonium citrate)] and depletion [DFO (deferoxamine)], respectively. However, in C. trachomatis‐infected HeLa cells, levels of IL‐10 remain higher, irrespective of availability of iron in comparison with their respective control. These results showed that secretion of IL‐10 and expressions of FHC have concordance. Further, to understand interdependence of IL‐10 and iron homoeostasis (regulation), the levels of IL‐10 were compared with iron‐responsive GFP (green fluorescent protein) expression in HeLa‐229 cells. The mean fluorescent intensities of GFP were in accordance with levels of IL‐10 in C. trachomatis‐infected cells. These results showed the association of secreted IL‐10, FHC and iron homoeostasis in C. trachomatis‐infected HeLa‐229 cells. This study provides insight into host–Chlamydia interaction at the crossroad of iron metabolism and immune responses and may help in realizing the potential of iron homoeostasis modulators in treatment of chronic chlamydial infection.