Antigenic repertoire of XXXX transmission-blocking vaccine candidates from the Indian subcontinent.

@entity535 @entity311 @entity3965
BACKGROUND: Genetic polymorphism is an inevitable component of a multistage infectious organism, such as the @entity311 parasite. By means of genetic polymorphism, parasite opts particular polymorph and reveals survival advantage. Pvs25 and pvs28 are sexual stage antigen genes, expressed at the ookinete stage inside the mosquito gut, and considered as potential transmission-blocking vaccine candidates. This study presents sequence variations in two important transmission blocking antigen genes pvs25 and pvs28 in the field isolates of @entity3965 from the Indian subcontinent. METHODS: One hundred microscopically diagnosed @entity3965 isolates were collected from five geographical regions of India. Pvs25 and pvs28 genes were PCR amplified and sequenced to assess sequence variation among field isolates. RESULTS: A total of 26 @entity535 substitutions were observed in Pvs25 (10) and Pvs28 (16) among field isolates of @entity3965 . Tandem repeat polymorphism observed in pvs28 shows 3-6 tandem repeats in the field isolates. Seven and eight novel @entity535 substitutions were observed in Pvs25 and Pvs28, respectively in Indian isolates. Comparison of @entity535 substitutions suggests that majority of substitutions observed in global isolates were also present in Indian subcontinent. A single haplotype was observed to be major haplotype among isolates of Delhi, Nadiad, Chennai and Panna except in isolates of Kamrup. Further, population comparison analyses suggest that @entity3965 isolates inhabiting in north-eastern region (Kamrup) were distantly related with the isolates from remaining parts of the country. Majority of the @entity535 substitutions observed in Indian isolates were more identical to the substitutions reported from isolates of Thailand and Bangladesh. CONCLUSION: Study uncovered many new @entity535 substitutions as well as a predominance of single haplotype in Indian subcontinent except in north-eastern region of the country. The @entity535 substitutions data generated in this study from different geographical regions of the Indian subcontinent could be helpful in designing a more effective anti-malarial transmission-blocking vaccine.
