The role of CD4 cells in protective immunity to Brugia pahangi

The BALB/c mouse immunized sub-cutaneously (s.c.) with 45 kRad attenuated third stage larvae (L3) of the lymphatic filarial nematode Brugia pahangi is strongly immune to a challenge infection (75–100% reduction in recovery at day six post challenge). Analysis of spleen cell supernatants from immunized mice re-stimulated in vitro, with parasite antigen or the non specific T cell mitogen Con-A reveals a cytokine profile (IL-4, IL-5 and IL-9) which indicates that the Th2 subset of CD4 cells has been expanded. In an attempt to formally prove a critical role for CD4 cells in immunity in this model system, immunized mice were given either anti-CD4 or anti-CD8 neutralizing antibodies. Administration of anti-CD4 antibody had a significant and detrimental effect on the immune response whereas anti-CD8 antibody had a negligible effect on immunity. The efficacy of antibody in neutralizing their target cells was determined by fluorescence activated cell sorting analysis (FACS). Spleen cells from anti-CD4 treated immunized mice, when re-stimulated with parasite antigen had a significantly reduced potential to secrete IL-4, IL-5 and IL-9 in vitro and serum from these mice had reduced levels of parasite specific IgG and IgE. These results demonstrate a critical role for CD4 T cells in host protective immunity to B. pahangi in vivo and strongly suggest that some component of the Th2 response plays an important role in the immune response elicited in this model system

Articulation and Clarification of the Dendritic Cell Algorithm

Abstract. The Dendritic Cell algorithm (DCA) is inspired by recent work in innate immunity. In this paper a formal description of the DCA is given. The DCA is described in detail, and its use as an anomaly detector is illustrated within the context of computer security. A port scan detection task is performed to substantiate the influence of signal selection on the behaviour of the algorithm. Experimental results provide a comparison of differing input signal mappings