Evaluation of Mucosal Humoral and Cellular Immune Responses to HIV in External Secretions and Mucosal Tissues

The mucosal immune systems of the genital and intestinal tracts are considered as the most frequent sites of HIV-1 entry, displaying remarkable immunological differences in the systemic immune compartment which must be considered in the evaluation of humoral and cellular immune responses to HIV- 1. Marked differences in the fluids from the genital and intestinal tracts and in plasma with respect to the Ig isotypes, their levels, molecular forms and distinct effector functions must be taken into consideration in the evaluation and interpretation of humoral immune responses. Because of the low levels and highly pronounced variation in Ig content, HIV-1-specific antibody concentrations should always be related to the levels of total Ig of a given isotype. This practice will avoid inevitable differences due to the small volumes of collected fluids and sample dilution during the collection and processing of samples from external secretions. Furthermore, appropriate controls and immunochemical assays should be used to complement and confirm results generated by ELISA, which is prone to false positivity. In the evaluation of antibodymediated virus neutralization in external secretions, precautions and rigorous controls must be used to exclude the effect of innate humoral factors. The evaluation of cell-mediated immune responses in mucosal tissues is difficult due to the low yields of cells obtained from tissue biopsies or cytobrush scrapings. Furthermore, tissue biopsies of, for exa...
Source: Current Immunology Reviews - Category: Allergy & Immunology Source Type: research