Mechanism of protection provided by active immunization with porins in mice challenged with Salmonella typhi.

Oxygen free radical (OFR) generation capacity of peritoneal macrophages was studied by chemiluminescent technique. Chemiluminescent (CL) response of macrophages from control, infected and immunized-infected mice was observed using non specific (Latex) and specific (S. typhi, cells and porins) stimulants at different time intervals. CL response was found to be significantly higher in immunized-infected group throughout the study period using all the three stimulants as compared to that in the infected as well as uninfected control mice. The mode of action of porin vaccine in increasing capacity of generating OFR is probably through increased expression of porin (protein) as well as carbohydrate receptors on the macrophage surface which leads to the stimulation of the whole caseade of respiratory burst or through the increase in the respiratory burst enzyme activities linked with each receptor or both.