Comparison of immunogenical potency of Leishmania major (MRHO/IR/ 75/ER) antigens prepared by 3 different methods in conjunction with Alum-Naltrexone adjuvant in BALB/c mice

Objectives: To evaluate the immunization ability of three Leishmania major antigens including formaline
killed promastigotes (FKP), autoclaved Leishmania major (ALM) and soluble Leishmania antigen (SLA), they
were used to immunize BALB/c mice in association with a mixture of alum and naltrexone (Alum-Nalt) as
adjuvant.
Methods: Each mouse from any of three groups received FKP, ALM or SLA antigens. Three additional
groups were injected with same antigenes plus Alum-Nalt. One more group was injected with PBS to
be the control group. Booster injections were given at 14th and 28th days. Two weeks after the last
immunization, seven mice from each group were exposed to live promastigotes subcutaneously, and skin
lesion formation among each mouse was monitored and recorded for 60 days. One week later, cellular
and humoral immune responses of other immunized mice were evaluated by measuring the serum levels
of anti-ALM-specific IgG1, IgG2a and total IgG antibodies, splenic anti-ALM-specific IFN-c and IL-5 production
and splenic lymphocyte proliferation after adding ALM.
Results: In the challenge test, all mice immunized with ALM antigen and Alum-Nalt were prevented from
formation of skin ulcer. Also, the mice from the same group showed higher IFN-c production and splenic
lymphocyte proliferation and higher anti-ALM-specific IgG2a production.
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