THE EFFECT OF IFN-GAMMA, ALUM AND COMPLETE FREUND ADJUVANT ON TNP-KLHINDUCED IGG(1), IGE AND IGG(2A) RESPONSES IN MICE

ADJUVANTS are considered to play an important role in directing the is otype and amount of antibodies produced upon immunization by conductin g the development of either Th-1 or Th-2 cells upon T-cell stimulation . This is based on the different cytokine production patterns that wer e observed after in vitro restimulation of T cells isolated from mice immunized with antigen either adsorbed on alum or emulsified in comple te Freund adjuvant (CFA). However, other studies suggest that primaril y the type of antigen determines which isotypes are produced and to wh at extent. In these studies, however, IgE was not determined. Therefor e, this study examined whether alum and CFA influenced the amount and/ or ratio of IgG(1), IgE and IgG(2a) produced after TNP-KLH immunizatio n. Similar levels of IgG(1), IgE and IgG(2a) antibodies were found upo n Immunization with TNP-KLH either adsorbed on alum or emulsified in C FA. Moreover, administration of IFN-gamma in combination with TNP-KLH adsorbed on alum did not increase the amount of IgG(2a) produced IFN-g amma treatment resulted in an increased IL-6 and decreased IFN-gamma p roduction by spleen cells upon Con A stimulation, whereas It did not c hange the IL-4 production in similar conditions. The presented results suggest that upon immunization with TNP-KLH high IL-4 levels are prod uced, resulting in an antibody response that is dominated by IgG(1), i ndependent of the adjuvant employed. The IL-4 inducing property of TNP -KLH is substantiated by the ending that repeated immunization of mice with TNP-KLH, without adjuvant, increases the serum total IgE level. The presented data suggest that the carrier part of TNP-KLH preferenti ally results in Th-2 cell activity after which the adjuvant merely enh ances the antibody responses generated.