Attempts were made to evaluate the protective efficacy of Brugia malayi
thioredoxin peroxidase (BmTPX) in a mouse model. Mice immunized with a
protein vaccine containing rBmTPX developed higher titres (1:5,000/1:10,000) of anti-BmTPX
antibodies, compared with the mice immunized with the
alum control. There was a higher level of cellular proliferative response in mice immunized with BmTPX compared with the
alum control (p < 0.05), which was associated with a Th2-type of response. In order to compare the prophylactic efficacy of BmTPX in natural
infection, we evaluated the human immune responses to these
antigens in endemic normals (EN) and infected individuals (microfilaraemic and chronic pathology). Results showed that EN subjects carry BmTPX-specific
IgG1 and
IgG3 circulating
antibodies against natural exposure to
filariasis. Peripheral blood mononuclear cells from EN subjects responded strongly to rBmTPX by proliferating, as well as by secreting
interferon (IFN)-γ (Th1) and
IL-5 (Th2), a mixed type of response to rBmTPX. In the case of infected individuals, there was no IFN-γ or
IL-5 response. Thus, there was a clear dichotomy in the
cytokine production by infected versus EN individuals. Our findings suggest that BmTPX may be a suitable
antigen candidate for
lymphatic filariasis, but a further study is still required.