IMMUNOPHENOTYPING OF CANINE BRONCHOALVEOLAR AND PERIPHERAL-BLOOD LYMPHOCYTES

The immunophenotype of canine lymphocytes obtained by bronchoalveolar lavage (BAL) was investigated and compared with that of peripheral blo od leukocytes (PBL). Indirect immunofluorescence, generated by monoclo nal antibodies (mAb) specific for canine CD5, CD4, CD8, CD45pan, CD45R A, MHCII and THY-I, was detected by Bow cytometry. In comparison with PBL, in BAL there are fewer lymphocytes positive for CD45RA (75.4 +/- 12.6% vs. 42.3 +/- 19.4%; P<0.05) and MHCI I (97.0 +/- 2.9% vs. 74.0 /- 7.6%; P<0.01), while there are more cells positive for CD8 (19.0 +/ - 3.6% vs. 29.5 +/- 12.0%; P<0.05). Thus there is a lower CD4/CD8 rati o in the cell compartment accessible by BAL (2.2 +/- 0.3 vs. 1.3 +/- 0 .6; P<0.005). The immunophenotype may be stable over time, as indicate d by reexamination of cells obtained from one dog at four times over 1 year. Investigating the phenotype of lymphocytes from three different locations of the right lung, the cranial lobe lymphocytes show a lowe r CD4/CD8 ratio in comparison with PBL (1.81 +/- 0.35 vs. 1.12 +/- 0.3 1, It = 5; P<0.02). In general, less MHCII positive lymphocytes (P<0.0 01) and greater immunophenotype variability of results were found in t hese separate samples compared with pooled samples from these location s.