Hedstrom R C, Campbell J R, Leef M L, Charoenvit Y, Carter M, Sedegah M, Beaudoin R L, Hoffman S L
Infectious Diseases Department, Naval Medical Research Institute, Bethesda, MD 20814-5055.
Bull World Health Organ. 1990;68 Suppl(Suppl):152-7.
Monoclonal antibody NYS4 recognizes a single 140 kDa antigen on the surface of Plasmodium yoelii sporozoites, an antigen which is distinct from the extensively characterized circumsporozoite (CS) protein. To more thoroughly characterize this additional surface component, a genomic expression library was screened with NYS4 and an immunoreactive clone (M4) was obtained which expressed part of the antigen gene. The deduced amino acid sequence of the M4 peptide included two unique repetitive sequences of amino acids and a conserved sequence motif which is found in several proteins including the CS protein (region II). The cloned DNA hybridized to a PCR (polymerase chain reaction) amplified sporozoite mRNA demonstrating the sporozoite-stage expression of this gene. A synthetic peptide of one of the repeats, (Asn-Pro-Asn-Glu-Pro-Ser), was recognized by NYS4 and mice immunized with (Asn-Pro-Asn-Glu-Pro-Ser)3 conjugated to KLH (keyhole limpet haemocyanin) produced high levels of antibodies that reacted with the surface of sporozoites and specifically to the 140 kDa antigen. Thus, at least two different proteins are on the surface of the P. yoelii sporozoite indicating that the immunoreactive exterior of the infective stage of malaria parasites is more antigenically complex than previously thought.
单克隆抗体NYS4识别约氏疟原虫子孢子表面的一种单一的140 kDa抗原，该抗原不同于已被广泛研究的环子孢子（CS）蛋白。为了更全面地表征这种额外的表面成分，用NYS4筛选了一个基因组表达文库，并获得了一个免疫反应性克隆（M4），该克隆表达了部分抗原基因。M4肽推导的氨基酸序列包含两个独特的氨基酸重复序列和一个保守的序列基序，该基序存在于包括CS蛋白（区域II）在内的几种蛋白质中。克隆的DNA与聚合酶链反应（PCR）扩增的子孢子mRNA杂交，证明了该基因在子孢子阶段的表达。NYS4识别其中一个重复序列的合成肽（Asn-Pro-Asn-Glu-Pro-Ser），用与钥孔血蓝蛋白（KLH）偶联的（Asn-Pro-Asn-Glu-Pro-Ser）3免疫的小鼠产生了高水平的抗体，这些抗体与子孢子表面反应并特异性地作用于140 kDa抗原。因此，约氏疟原虫子孢子表面至少有两种不同的蛋白质，这表明疟原虫感染阶段的免疫反应性外部比以前认为的在抗原上更复杂。
