ClustalW sequence alignment of apicomplexan, kinetoplastid, and human acidic ribosomal P2 proteins. Predicted ribosomal protein P2 amino acid sequences from T. gondii (GenBank accession number XM_002364187), Sarcocystis neurona (GenBank accession number BQ784279), P. falciparum (GenBank accession number U78753), Eimeria tenella (GenBank accession number AAK38885), C. parvum (GenBank accession number AF099744), B. bovis (GenBank accession number XP_001611755), Theileria parva (GenBank accession number XP_764936), Homo sapiens (GenBank accession number AAA36472), L. infantum (GenBank accession number XP_001467169), and T. cruzi (GenBank accession number CAA52946) were aligned by using the ClustalW2 sequence alignment program (30). The human SLE P-protein consensus sequence is underlined in the human sequence (32). The carboxy-terminal 15-amino-acid peptide (EEEEEEGDLGFSLFD) recognized by IgG antibodies from P2-positive Haitian sera is indicated in boldface with underlining in the C. parvum P2 sequence. The linear epitope recognized by mouse monoclonal antibody 1D6 is underlined in italics in the C. parvum P2 sequence.