Immunogenicity of soluble and particulate antigens from Leishmania donovani: effect of glucan as an adjuvant

Abstract

The protective efficacy of glucan as an adjuvant with killed promastigotes of Leishmania donovani was compared with that of soluble or particulate fractions of the parasite. When these vaccine preparations were injected either intravenously or subcutaneously in CF-1 mice, glucan potentiated resistance against L. donovani infections as reflected by significant reductions in hepatic amastigote counts relative to infected control mice. The leishmanial antigens alone afforded no protection. Serum direct agglutination titers to leishmanial antigens were highest in all groups given the vaccine intravenously, whereas the delayed-type hypersensitivity response to the antigen was positive only in groups immunized subcutaneously with glucan as an adjuvant. Some index of protection and immune response against visceral infection with the parasite was seen in groups vaccinated with glucan and soluble antigens. However, the protection afforded by glucan and particulate antigens of L. donovani more closely paralleled the resistance of mice treated with glucan and unfractionated killed promastigotes. Further antigenic analysis of particulate fractions of L. donovani may optimize effective immunization when used with appropriate adjuvants, e.g., glucan.

β-Glucan and parasites

“…Glucan offered protection against L. amazonensis via stimulation of NK cell activities (Yatawara et al, 2009). It is important to note that whereas different authors used different routes of glucan administration, the effects of glucan were same application (Cook and Holbrook, 1983; Novak and Vetvicka, 2008), which further supports the fact that glucan is active via all ways of administration.…”

“…Another interesting approach demonstrating the effectiveness of glucan was its use in an experimental vaccine based on L. donovani promastigotes. This vaccine offered significant protection regardless the route of application (Cook and Holbrook, 1983; Novak and Vetvicka, 2008). These data were based on older studies showing good effects of intravenous glucan injections and even stronger stimulation by glucan-promatostigotes combination (Cook and Holbrook, 1983).…”

“…This vaccine offered significant protection regardless the route of application (Cook and Holbrook, 1983; Novak and Vetvicka, 2008). These data were based on older studies showing good effects of intravenous glucan injections and even stronger stimulation by glucan-promatostigotes combination (Cook and Holbrook, 1983). Similar data were obtained using a hamster model, where besides the effects of a glucan-prostigmatoses combination, significant protection was found after application of glucan alone, both in vivo and in vitro (Cook et al, 1982).…”

β‐glucan as a new tool in vaccine development

“…Soluble β‐1,3‐D glucans have been shown to protect against infection with both bacteria and protozoa in several experimental models and to enhance antibiotic efficacy in infections with antibiotic‐resistant bacteria. The protective effect of glucans has been seen in experimental infection with Leishmania major , L donovani , Candida albicans , Toxoplasma gondii , Streptococcus suis , Plasmodium berghei , Staphylococcus aureus , Escherichia coli , Mesocestoides corti and Trypanosoma cruzi . It is particularly interesting that glucan has been found to protect against anthrax infection .…”

Beta Glucan: Supplement or Drug? From Laboratory to Clinical Trials

“…Based on the first wave of studies, glucan has been established in protection against infection. The protective effects of glucan application were shown in experimental models of infection with Leishmania major , L. donovani , Candida albicans , Toxoplasma gondii , Streptococcus suis , Plasmodium berghei , Staphylococcus aureus , Escherichia coli , Mesocestoides corti , Trypanosoma cruzi , Eimeria vermiformis , and Bacillus anthracis [27,28,29,30,31,32,33,34,35,36,37,38].…”