Administration of beta-glucan following Leishmania major infection suppresses disease progression in mice.

The potential of beta-glucan (glucan) to suppress the progression of lesions caused by virulent strains of Leishmania major in genetically susceptible BALB/c mice when administered post challenge was evaluated. Glucan particles (glucanp) prepared from Saccharomyces cerevisiae were injected i.v. at 7-day intervals starting 7 days after parasite challenge. Four injections gave a more rapid and a higher extent of suppression than 1, 2 or 3 injections. Mice receiving only parasites, a glucose solution, starch particles or glucanp by the i.p. route showed a progressive increase in footpad thickness and developed ulcerating lesions. An alkali solubilized glucan (glucanas) was injected (50 micrograms, 200 micrograms and 400 micrograms/mouse) 4 times at 4 day intervals either i.v. or i.p. starting four days post parasite challenge. Glucanas injection by either route blocked lesion development; the 50 micrograms treatment had already substantial effects and 400 micrograms in the i.p. route prevented even the initial stages of lesion formation. Touch prints from the lesion area and from the liver of mice receiving 200 micrograms glucanas were amastigote free. The anti Leishmania antibody titre of glucanas treated mice was lower and their sera recognized fewer antigens than that of control Leishmania bearing mice.