An avirulent lipophosphoglycan-deficient Leishmania major clone induces CD4 super(+) T cells which protect susceptible BALB/c mice against infection with virulent L. major

• Published in: Infection and immunity Vol. 61; no. 12; pp. 5205 - 5213
• Main Authors: Kimsey, P B, Theodos, C M, Mitchen, T K, Turco, S J, Titus, R G
• Format: Journal Article
• Language: English
• Published: 01.01.1993
• Subjects: Leishmania major
• ISSN: 0019-9567

An avirulent clone of Leishmania major was used to immunize susceptible BALB/c mice against challenge with virulent L. major. By using the immunized animals as a source of cells, CD4 super(+) parasite-specific T-cell lines could be generated in vitro which, when adoptively transferred to naive BALB/c recipients, conferred marked protection against challenge with virulent L. major. Compared with CD4 super(+) parasite-specific T-cell lines generated from nonimmunized BALB/c mice infected with L. major, the protective T-cell lines generated from immunized mice produced substantially less interleukin-4 and substantially more tumor necrosis factor and interleukin-2. Interestingly, the protective CD4 super(+) T cells did not mediate L. major specific delayed-type hypersensitivity in vivo and proliferated in vitro only in response to living L. major and not to frozen-and-thawed antigen preparations of the parasite. Finally, the avirulent clone of L. major was found to express the major surface glycolipid of L. major, lipophosphoglycan, at a level that was sixfold less than was sixfold less than expression of this molecule by virulent L. major.