THE IMMUNODOMINANT EIMERIA-ACERVULINA SPOROZOITE ANTIGEN PREVIOUSLY DESCRIBED AS P160 P240 IS A 19-KILODALTON ANTIGEN PRESENT IN SEVERAL EIMERIA SPECIES/

A lambda Zap II cDNA expression library, constructed from Eimeria acer vulina (PAPa46 strain) sporulated oocyst stage, was screened with sera raised to E. acervulina or Eimeria tenella oocysts in order to isolat e clones coding for antigens common to the two species, Most of the cl ones isolated were derived from the same gene. Antisera raised to a re combinant glutathione-S-transferase fusion protein 1P reacted with an antigen of 19 kDa in immunoblot of E. acervulina sporulated and unspor ulated oocysts. Immunofluorescence of E. acervulina sporozoites indica ted that the antigen is located in the cytoplasm. The anti-1P antisera reacted on immunoblots of E. tenella with a 19-kDa antigen and by imm unofluorescence on E. tenella, Eimeria maxima and Eimeria falciformis sporozoites, indicating that the antigen is conserved in Eimeria speci es. DNA sequencing indicated that the sequence was almost identical to that of clone cSZ1 previously described by Jenkins et al. [1] using E . acervulina strain #12. The 1P insert hybridized to a 1150-nt mRNA fr om E. acervulina PAPa46 strain and strain #12, a size consistent with the observed molecular weight of the protein.