To examine more globally the differences in responsiveness to filarial infections between persons with relatively newly acquired infection and those with lifelong exposure and to evaluate more comprehensively the T cell responses (both CD4+ and CD8+) seen in these two groups, we utilized spotted, human microarrays and RNA from either CD4+ or CD8+ T cells (ex vivo) and in response to filarial and nonfilarial antigens. The gene discussed is CD8A; the disease is infection.