New proteins (I) from the causative virus of porcine reproductive and respiratory syndrome (PRRS) are any of the proteins encoded by open reading frames (ORF) 2-7 of PRRS-Olot. Also new are recombinant baculoviruses able to express at least one recombinant protein corresponding to these ORF. The specification includes (1) the sequence of a 3383 bp fragment cloned from PRRS-Olot and contg. ORF 2-7, and (2) amino acid sequences (249, 265, 183, 200, 173 and 128 amino acids) encoded by each of ORF 2-7.