Plasmodium falciparum: Restricted polymorphism of T cell epitopes of the circumsporozoite protein in Brazil

• Published in: Experimental parasitology Vol. 71; no. 4; pp. 386 - 392
• Main Authors: Yoshida, Nobuko, Di Santi, Silvia M, Dutra, Araripe P, Nussenzweig, Ruth S, Nussenzweig, Victor, Enea, Vincenzo
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.11.1990; Elsevier
• Subjects: Amino Acid Sequence; Animals; Antigens, Protozoan - genetics; Base Sequence; Biological and medical sciences; Brazil; CS gene; DNA, Protozoan - analysis; DNA, Protozoan - genetics; Electrophoresis, Agar Gel; Epitopes - genetics; Fundamental and applied biological sciences. Psychology; Genetic Variation; Molecular Sequence Data; Plasmodium falciparum; Plasmodium falciparum - genetics; Plasmodium falciparum - immunology; Polymerase Chain Reaction; Polymorphism; Polymorphism, Genetic; Protozoa; Protozoan Proteins; Systematics. Geographical distribution. Morphology. Cytology; T cell epitopes; T-Lymphocytes - immunology; South America; Brazil; America; Plasmodium falciparum; CS gene; Deoxyribonucleic acid (DNA); Phosphate-buffered saline (PBS); T cell epitopes; Circumsporozoite (CS); Ethylenediaminetetraacetate (EDTA); Polymerase chain reaction (PCR); Cytotoxic T lymphocyte (CTL); Polymorphism; Human; Protozoa; Antigenic determinant; Gene; DNA; T-Lymphocyte; Parasite; Cytotoxicity; Electrophoresis; Sporozoa
• ISSN: 0014-4894; 1090-2449
• DOI: 10.1016/0014-4894(90)90064-J

We examined the extent of variation of the 3′ region of the Circumsporozoite gene among Plasmodium falciparum isolates through amplification of a selected DNA fragment followed by DNA sequencing. A total of 32 isolates were analyzed, of which 24 were from Amazon endemic areas in Brazil and 8 from widely separated geographical regions in the world. Among Brazilian isolates only 2 variants were detected: 19 displayed the same sequence of strain 7G8 whereas the 4 remaining isolates differed from the 7G8 strain at five nucleotide positions which also led to amino acid changes. Variation was restricted to one of the T-helper epitopes while the sequence identified as a cytotoxic T cell epitope was conserved in all Brazilian isolates. P. falciparum samples from other geographical regions in the world showed sequences distinct from those of Brazilian isolates. However, some constancy could be observed within that variation. For instance, the most frequent nucleotide substitutions, from A to C at nucleotide positions 1015 and 1024, were the same in all isolates.