Abstract: To study the biological function of porcine alveolar macrophages FcγRⅢ，we cloned cDNA of FcγR Ⅲ gene from total RNA of porcine alveolar macrophages (PAM) by reverse tmnscription-polymerase chain reaction (RT-PCR) and analysised its sequence in this study. Sequence analysis showed that the porcine FcγR Ⅲ cDNA cloned was 820 bp in length which contained 771 bp open reading frame(ORF).The nucleotide sequence of porcine FcγR Ⅲ shared 99.9％ homology with the published sequence(AF237453)．The comparison of the deduced amino acids sequence of porcine FcγRⅢ with those of human，cattle，horse，sheep，monkey，dog，cat amd mouse showed that the amino acids homology similarity were 61.6%,62.9%,55.3%,62.2%, 63.0%,59.0%,61.8% and 53.2% respectively．The analysis of deduced amino acids sequence indicated that FcγRⅢ was a typical type I transmembrane protein with two Ig-like domains in extracellular region．The clone of porcine alveolar macrophages FcγR Ⅲ lay the foundation for further study of structure and function of porcine alveolar macrophages FcγRⅢ.

Key words: porcine alveolar macrophages FcγRⅢ; cloning; sequence analysis