immunology of infectious and parasitic diseases - XXXVII Congress ...

VACCINATION WITH SM10.3 ANTIGEN, A MEMBER OF THE MICRO-EXON
GENE FAMILY-4 (MEG-4) FROM SCHISTOSOMA MANSONI, PROTECTED
MICE AGAINST PARASITE CHALLENGING
VICENTE DE PAULO MARTINS¹; SUELLEN BATISTONI DE MORAIS¹;
NATAN RAIMUNDO GONÇALVES DE ASSIS¹; BÁRBARA DE CASTRO
PIMENTEL FIGUEIREDO¹; CARINA DA SILVA PINHEIRO 2 ; NATASHA
DELAQUA RICCI 1 ; SÉRGIO COSTA OLIVEIRA¹.
¹ Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Brazil.
² Instituto de Ciências da Saúde, Universidade Federal da Bahia, Brazil.
Introduction: The flatworm Schistosoma mansoni is a blood fluke parasite that
causes schistosomiasis, a debilitating disease that occurs throughout the
developing world. Current schistosomiasis control strategies are mainly based
on chemotherapy, but many researchers believe that the best long-term
strategy to control schistosomiasis is through immunization with an antischistosomiasis
vaccine combined with drug treatment. The Sm10.3 is a 28 kDa
protein expressed in the digestive tract of cercariae, male and female adult
worms. Its location is restricted to the esophageal gland and its function may be
related to coagulation and digestion of the host red blood cells, processes
critical to the survival of the parasite.
Methods and Results: Here, we describe the cloning and expression of the
Sm10.3 gene from S. mansoni and its potential as a recombinant vaccine.
Quantitative real time PCR (qPCR) analysis revealed that Sm10.3 was highly
expressed in the schistosomulum stage. Immunization of mice with rSm10.3
induced a mixed Th1/Th2 type of immune response with production of IFN-
and TNF-, and low levels of IL-5 into the supernatant of splenocyte cultures.
The protection engendered by this vaccination protocol was confirmed by 32%
reduction in worm burden, 43% reduction in eggs per gram of hepatic tissue,
24% reduction in the number of granulomas per area and 45% reduction in the
granuloma fibrosis.
Conclusion: Taken together, the data herein support the potential of surface
exposed antigens from the S. mansoni digestive tract as vaccine candidates.
Financial Support: CNPq, FAPEMIG, Capes.