Cell-mediated immunity by Th1-type CD4؉ T cells is the predominant host defense mechanism against mucosal candidiasis. However, studies using an estrogen-dependent murine model of vaginal candidiasis have demonstrated little to no change in resident vaginal T cells during infection and no systemic T-cell infiltration despite the presence of Candida-specific systemic Th1-type responses in infected mice. The present study was designed to further investigate these observations by characterizing T-cell activation and cell adhesion molecule expression during primary and secondary C. albicans vaginal infections. While flow cytometry analysis of activation markers showed some evidence for activation of CD3 ؉ draining lymph node and/or vaginal lymphocytes during both primary and secondary vaginal Candida infection, CD3؉ cells expressing the homing receptors and integrins ␣ 4  7 , ␣ M290  7 , and ␣ 4  1 in draining lymph nodes of mice with primary and secondary infections were reduced compared to results for uninfected mice. At the local level, few vaginal lymphocytes expressed integrins, with only minor changes observed during both primary and secondary infections. On the other hand, immunohistochemical analysis of vaginal cell adhesion molecule expression showed increases in mucosal addressin cell adhesion molecule 1 and vascular cell adhesion molecule 1 expression during both primary and secondary infections. Altogether, these data suggest that although the vaginal tissue is permissive to cellular infiltration during a vaginal Candida infection, the reduced numbers of systemic cells expressing the reciprocal cellular adhesion molecules may preempt cellular infiltration, thereby limiting Candida-specific T-cell responses against infection.
SUMMARY Mucosal cell-mediated immunity (CMI) by CD4+ T cells is postulated to be important for host defence against several vaginal pathogens. In addition to the recognized phenotypic distinctions of resident vaginal T lymphocytes, we recently provided evidence by¯uorescence-activated cell sorter (FACS) that murine vaginal CD4 + T lymphocytes, are differentially recognized by two epitopedistinct anti-CD4 antibodies, suggesting that the CD4 protein on vaginal CD4+ cells is atypically expressed. In the present study, we con®rm this by FACS and immunohistochemistry under nondenaturing conditions using two additional anti-CD4 antibodies. However, positive immunohistochemical staining of vaginal CD4+ cells under denaturing conditions revealed that the CD4 epitope in question is indeed present within the CD4 protein. Using reverse transcription polymerase chain reaction, ampli®cation of CD3, T-cell receptor-b (TCR-b), and TCR-d mRNA from lymph node and vaginal tissue, and CD4 mRNA from lymph node tissue was demonstrable. In contrast, ampli®cation of CD4 mRNA from vaginal tissue, vaginal enriched lymphoid cells, or a puri®ed (FACS-sorted) population of vaginal-speci®c CD4 + cells using two distinct primer sets was not demonstrable. Altogether, our results provide evidence that the CD4 protein on vaginal CD4 + T cells is conformationally distinct compared with its systemic counterpart, either as a result of a unique CD4 mRNA sequence or from a stable interaction of soluble CD4 with the surface of vaginal T cells.
The application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to the analysis of blood serum leads to the observation of a large variety of reproducible mass spectral peaks corresponding to blood components. In this study, the use of MALDI-TOFMS was developed as a tool for monitoring immune response to bacterial infection. Employing the MALDI-TOFMS approach, the levels of many components of blood were found to be immune response independent whereas others were found to correlate directly with the response of the immune system to two known types of bacteria (Staphylococcus aureus and Enterococcus faecalis). The methodologies reported here should be useful for the rapid monitoring of blood, especially that of the immune response mechanisms in various animal species.
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