The present invention provides isolated polynucleotide molecules comprising nucleotide sequences encoding GRA1, GRA2, SAG1, MIC1 and MAG1 proteins from Neospora caninum, as well as recombinant vectors, transformed host cells, and recombinantly-expressed proteins. The present invention further provides a polynucleotide molecule comprising the nucleotide sequence of the bidirectional GRA1IMAGI promoter of N. caninum. The present invention further provides genetic constructs based on the polynucleotide molecules of the present invention that are useful in preparing modified strains of Neospora cells for use in vaccines against neosporosis.