Cellular adjuvant activity of peanut, cottonseed and rice oils
E. F. Mota1; A.C.M. Silva1; M. F. Sindeaux2; D.C.S.N. Pinheiro3; M. M. L. Pompeu2; M.G. Silva Lima1 and D. Fernandes de Melo1.
1 Depto Bioquímica e Biologia Molecular and 2Depto Patologia e Medicina Legal, UFC-CE. 3Faculdade de Veterinária, UECE-CE.
Each substance that is able to amplify a particular situation in the cascade of immunological events, leading to a better immunological response, can be defined as an adjuvant. In this study, we investigated the adjuvant effect of cottonseed (SCT), peanut (SPN) and rice (ERC) oils in relation to protection against murine leishmaniasis after vaccination with Leishmania amazonensis. The Leishmania antigen was prepared according to Mayrink et al. (1979). Mice were subcutaneous or intraperitoneally immunized with the antigen emulsified or not with the oils. Non-immunized mice received equal volume of saline. Two weeks after the booster, the mice were challenged with 106 viable stationary-phase promastigotes in the hind footpad. Lesion sizes were weekly measured with a dial gauge caliper. The animals were killed 5 months post-infection to assess parasitological loads in the draining lymph nodes, according to Silva et al. (1994). The mice intraperitoneally immunized with antigen alone as well as antigen emulsified with ERC and SCT were protected from infection. Untreated as well as antigen-SPN mice developed similar and progressive lesions until the end of the experiment. Subcutaneously untreated mice developed lesions from the 8th weeks, antigen-SPN ones started developing lesions only from the 12th week and antigen-SCT started developing smaller lesions from the 8th week after infection. The lymph nodes from untreated mice presented a parasite load as high as lymph nodes from animals intraperitoneally immunized with antigen-SPN. Mice immunized with antigen alone as well as antigen emulsified with ERC and SCT presented negative parasite loads. The lymph nodes from untreated mice presented a higher parasite load than lymph nodes from mice subcutaneously immunized with antigen-SPN. Moreover antigen alone as well as antigen-ERC presented negative parasite loads. This variety of modulated immune response by vegetable oil emulsions is a differential in relation to other adjuvants and makes possible the use of these oils as tools in different procedures of immunization. It still worth mentioning, the fact that vegetable oils are biodegradable, cheap, easily acquired and safe.
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