Isolation and characterization of the 80000 dalton Plasmodium falciparum merozoite surface antigen

Abstract

The 80,000 dalton merozoite surface protein, derived from the 185,000-195,000 dalton schizont precursor, was isolated from detergent extracts of naturally-released merozoites using chromatographic procedures. A rabbit antiserum raised against this antigen was used for characterizing the 80,000 dalton fragment. The antiserum did not inhibit merozoite invasion or parasite growth in vitro, suggesting that this merozoite surface antigen is not directly involved in the invasion process of the merozoite into the host erythrocyte.

Use of a recombinant baculovirus product to measure naturally-acquired human antibodies to disulphide-constrained epitopes on the P. falciparum merozoite surface protein-1 (MSP1)

“…The proteins MSP183 and s42AA correspond respectively to large N-terminal and C-terminal [22,29] as Vale0. The C-terminus of MSP183 is unknown, but is shown here as being within block 8 of the MSP1 sequence, since the total molecular mass of the amino acid sequence of the Wellcome MSP1 from Vale0 to Gin764 is 80547 Daltons, and Gln764 lies within block 8 [28].…”

Isolation and functional characterization of Plasmodium falciparum merozoite antigens

“…of various proteins in the eluate was monitored by SDS-PAGE and fluorography. Fractions were kept frozen at -20°C until used [63].…”

“…These IgG fractions were used for in vitro invasion inhibition and growth inhibition assays in highly synchronous cultures. The negative in vitro inhibition of the anti-80 and the positive inhibition of the anti-46 rabbit IgG fractions are shown as examples, together with the corresponding tests for parasite growth inhibition [40,63].…”

“…Thus the N-terminus of the molecule appears to be blocked. This blockage does not result from the antigen preparation procedure since other merozoite antigens, prepared and isolated with the same techniques, show a free N.terminal end and N-terminal amino sequences can be obtained [63;Heidrich et al,in preparation]. It is hoped that it will be possible to obtain the amino acid sequence from the 46 kDa merozoite surface antigen from the corresponding nucleotide sequence.…”

Evaluation of Leishmania antigens preparation and storage for use in enzyme immunoassays

“…The study on time and temperature was intended as a means to critically ascertain optimum storage and temperature for the antigens, an important step for serum surveys where the use of only one antigen batch is prefered. As proteases inhibitors 18 have been used in parasitic antigenic extracts in an attempt to minimize the action of proteolitic enzymes we thought interesting to critically evaluate its influence on the alkaline antigen performance by means of its influence on serum GMT. 15 and ulcer imprint or biopsy 3 .…”