Abstract: A synthetic peptide comprising an amino acid sequence including the sequence Asp-Arg-Ala-X-Gly-Gln-Pro-Ala-Gly wherein X is selected from the group consisting of Asp and Ala, said peptide being capable of eliciting formation of antibodies recognizing the circumsporozoite protein of Plasmodium vivax sporozoites.

Abstract: Described is a antigen and antigenic amino acid sequence consisting of repeating units of the immunodominant epitope region of the circumsporozoite surface protein of a parasite of the genus Plasmodium. Also described is a related fusion protein produced by a recombinant microorganism and a vaccine for immunizing mammals against malaria.

Abstract: The present invention provides an immunoassay of general applicability. The assay detects an antigen by its inhibition of the reaction between the combining site of two antibodies. One of the antibodies binds antigen, and the second antibody binds to the combining site or idiotype of the first antibody. It is preferable that both the antibody that binds the antigen and the anti-idiotypic antibody are monoclonal antibodies. The assay provides a method for measuring concentrations of single epitopes without requiring purified antigen, and it is particularly useful for measuring the quantity of any nonpurified antigen present in low concentration in a mixture of antigens. The use of monoclonal antibodies as reagents is advantageous in providing an essentially unlimited supply of highly specific and standardized reagents, without the batch-to-batch variation encountered when using conventional polyclonal antibodies.

Abstract: Disclosed is a peptide antigen comprising an amino acid sequence of a non-repetitive epitope of the circumsporozoite protein of a sporozoite of the genus plasmodium said peptide having the property of eliciting formation of antibodies that bind to said nonrepetitive epitope on the sporozoite surface said peptide being synthetic, purified and substantially shorter in length than said protein.

Abstract: Disclosed are peptides comprising the amino acidsAsp-Arg-Ala-X-Gly-Gln-Pro-Ala-Glywherein X represents Asp or Ala, said peptides eleciting antibodies against the P. vivax circumsporozoite protein. Also disclosed are DNA sequences coding for such peptides.

Abstract: Synthetic peptides containing non-repeating epitopes of circumsporozoite derived protein antigen and which are substantially shorter in length than the intact antigen are disclosed. The peptides when administered to a host raise antibodies in that host that will bind to the circumsporozoite antigen on the parasite. Vaccines based upon these peptides, as well as means of raising antibodies to circumsporozoite antigens using the synthetic peptides are also disclosed.

Abstract: The present invention provides antisera and monoclonal antibodies directed against the sporozoite stage of the malaria parasite capable of providing protection against infection in both animals and humans. The invention further provides a purified antigen derived from sporozoites of the malaria parasite, the antigen being suitable for use as a vaccine against malarial infections in both animals and humans. The invention further provides means for preparing said antigen and a vaccine comprising said antigen.