Advanced Development of Leishmania Topical Skin Test Antigen
Final rept. 18 Jun 2009-31 Aug 2012
ALLERMED LABS INC SAN DIEGO CA
Pagination or Media Count:
The lysate of Leishmania tropica promastigotes is a complex mixture of substances, including proteins in the range of 8 kDa to 70 kDa. In Leishmania na ve adult humans, the lysate can cause sensitization manifest by the conversion of a negative to positive delayed-type hypersensitivity DTH skin test. This was observed on the third skin test with 30 ug and 50 ug doses of the crude lysate administered intradermally at monthly intervals. Fractionation of the lysate identified dominant proteins at 8 kDa, 20 kDa, and 56-58 kDa. Skin tests in L. tropica sensitized guinea pigs with each of these fractions revealed significant differences in the reactivity of the fractions. The 8 kDa fraction, which contained approximately 95 of the lysate mass, failed to elicit a positive DTH response. Conversely, the 20 kDa and 56-56 kDa fractions tested at 1.0 ug, 3.0 ug and 10.0 ug protein elicited strongly positive skin tests comparable in size and intensity to a 50 g dose of the crude promastigote lysate. In Leishmania na ve guinea pigs, the crude lysate and the 8 kDa, 20 kDa and 56-58 kDa fractions all exhibited sensitizing properties at the doses studied. Similar tests were not conducted in Leishmania na ve humans.
- Medicine and Medical Research