Pure protein from Leishmania donovani protects mice against both cutaneous and visceral Leishmaniasis

Nurit Rachamim*, Charles L. Jaffe

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

87 Scopus citations

Abstract

A protein purified from Leishmania donovani promastigotes, dp72, was shown to partially protect BALB/c mice against a challenge by this parasite. Immunized mice infected i.v. with 107 L donovani promastigotes showed a 0, 60, and 78% reduction in liver parasite burden compared with the control mice at each time point examined after challenge, 1, 20, and 108 days, respectively. Western blotting demonstrated that the sera from the immune mice, which reacted specifically with dp72 in lysates of L. donovani, cross-reacted with one major band in total homogenates of Leishmania major and Leptomonas collosoma. Lymphocyte proliferation to crude and pure parasite Ag was also examined in mice immunized with dp72. Strong proliferation was found at low concentrations of crude L. donovani Ag (0.5 μg/ml) and with pure dp72. Proliferation at higher concentrations to crude L. major and L. collosoma Ag was observed. Little or no reaction (stimulation index < 1.0) was seen with other pure leishmanial Ag, including gp70-2, the promastigote surface protease, and lipophosphoglycan. Depletion in vitro of the CD4+ T cell subset from immune spleen cells abolished proliferation to dp72, whereas depletion of CD8+ T cells enhanced proliferation to the pure Ag. Experiments in vivo showed that immunized mice treated with antibodies to either CD4+, CD8+, both Tcell subsets, or to IFN-γ had larger LPB (178,173,176, and 130%, respectively) after challenge with L. donovani than nonimmunized controls. Mice immunized with dp72 but treated with either PBS or mouse Ig showed reduced LPB, 81 and 61%, respectively, compared with the nonimmunized animals. BALB/c mice immunized with dp72 were also protected against L. may'orwhich causes cutaneous leishmaniasis. Immunized mice infected with either 104 or 106 promastigotes did not develop lesions. Limiting dilution assays confirmed the protection.

Original languageEnglish
Pages (from-to)2322-2331
Number of pages10
JournalJournal of Immunology
Volume150
Issue number6
StatePublished - 1993

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