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Immune humoral and cellular response of nelore bovines immunized with larvae extract (L2 and L3) of Dermatobia hominis (Linnaeus Jr., 1781)

Dermatobia hominis larvae cause ulcerative lesions and damage to subcutaneous tissue and skin of the host. Leather is the subproduct which undergoes major depreciation, making it difficult to industrial use. Nowadays, the chemical control is utilized against dermatobiosis, therefore it leads to rising toxic chemicals in the animals and environment. The immunological challenge with D. hominis larval extract may represent an important altervative for this parasitosis control. Humoral and cellular immune responses were tested in bovine using an antigenic extract prepared with D. hominis larvae. Three groups of 10 months old Nelore females were used. The first group (A) received immunogenic larval extract of D. hominis with fifteen-days interval between injections; the group (B) was the control and has not received any sort of treatment; and the group (C) received an ectoparasitecide treatment based on Dichlorvos associated to Cypermetrina. Aditionally, leucogram and levels of IgG against D. hominis by immunoassay technique were evaluated. As for the humoral immunity, animals from group A presented higher IgG production against D. hominis with maximum levels of circulating antibodies at the 45th day after the first injection. These animals also showed higher production of neutrophils, eosinophils and monocytes than those from groups B and C. The number of D. hominis larvae nodules observed in animals from the group C was 148.3% larger than those from group A and B. The evidence concerning both cellular and humoral immune responses as well as the reduction on nodules number are an indication that the immunization against D. hominis was partially protective for the immunized bovines.

Dermatobia hominis; humoral immunity; cellular immunity; larval extract

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