A vaccine vormulation containing Babesia bovis MSA-2 antigens elicits invasion-inhibitory antibodiesand IFN-gamma producing cells

GIMENEZ AM; FRANÇOSO KS; ERSCHING J; ICIMOTO MY; OLIVEIRA V; RODRIGUEZ AE; SCHNITTGER L; FLORIN-CHRISTENSEN M; RODRIGUES MM; SOARES IS

Conferencia; Vaccines R&D 2016; 2016

Bovine babesiosisis is a tick-transmitted disease posing a potential risk to more than 500 million cattle worldwide. The etiological agents are protozoa of the Babesia genus, of which B. bovis is the most virulent. Vaccines currently available are based on attenuated live parasites, and although they are generally effective ,they are difficult to produce and store, may co-transmit other pathogens, cause severe clinical symptoms, and result in death of animals older than one year of age. For these reasons, the development of a subunit vaccine against B. bovis would be safer and more attractive from an economic perspective, and, in addition, would be also recommended for adult bovines. In the present study, recombinant ectodomains of the glycosylphosphatidylinositol (GPI)-anchored MSA-2a1, MSA-2b, and MSA-2c B. bovis surface antigens were expressed in Pichia pastoris as secreted soluble peptides. The antigens were high-degree purified, and biochemically and immunologically characterized. A vaccine formulation was obtained by emulsifying a mixture of the three peptides with the adjuvant Montanide ISA 720, which elicited high IgG antibody titers against each of the antigens in mice. IgG antibodies generated against each MSA-antigen recognized merozoites and significantly inhibited the invasion of bovine erythrocytes. Cellular immune responses were detected by IFN-gamma and TNF-alpha production of splenic and lymph node CD4+ T cells after stimulation with MSA-2a1 or MSA-2c. These data strongly suggest the high protective potential of this vaccine formulation. Supported by CNPq/CONICET (490395/2011-2), INCTV-CNPq FAPESP,ANPCyT (PICT 2010-0438) and INTA (PNBIO 1131034).