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To shed clarity on the dichotomy of reported results relative to the significance of T helper-1 vs T helper-2 immune responses in onchocerciasis, we compared the survivability of Onchocerca volvulus third-stage larvae (L3) in immunized mice that had either a targeted disruption of the Interleukin-4 or Interferon-gamma gene. Treatment groups consisted of control mice and mice immunized with irradiated O. volvulus L3. All mice were challenged with diffusion chambers containing viable L3. Vaccinated IL-4-/- were unable to kill this larval target. In contrast, vaccinated IFN-γ-/- and C57BL/6 mice, exhibited high levels of killing, had elevated levels of IL-4 and significantly greater numbers of eosinophils in their diffusion chambers than the IL-4-/-. Whereas, levels of IFN-γ in all three groups of immunized mice were equivalent to those of control mice, levels of IL-5 were elevated, even in the IL-4-/-, indicating that cytokines other than IL-4 were involved in its production. The protective immune response to third-stage larvae of O. volvulus in mice vaccinated with irradiated larvae has an absolute IL-4 requirement. [ABSTRACT FROM AUTHOR]

Highlights findings of a study by Jeffrey Bethony and colleagues which examined the antibody responses of individuals from hookworm endemic areas of Brazil and China against antigens secreted by third-stage infective hookwork larvae, and Ancylostoma Secreted Proteins (ASP) 1 and 2. Cloning and expression of ASPs; Association between the risk of hookworm infection and increased levels of IgG4 anti-ASP-2; In vitro and in vivo effects of anti-ASP-2 antibody in canine vaccination with ASP-2.