CD5-low expression lymphocytes in canine peripheral blood show characteristics of natural killer cells.
NK cell markers and receptors have been discovered in many mammalian species, such as humans, mice, rats, pigs, and cows. However, there is still a lack of information concerning NK cell markers or receptors in canines. We have discovered that canine CD5-low density (CD5lo) cells in PBL are closely associated with NK cell characteristics. CD5lo cells comprised 14.9 +/- 6.68% of the total PBL. A high proportion of the CD5lo cell population expressed CD3 (96.6%), CD8alpha (77.7%), CD8beta (53%), alpha/beta TCR (83%), and CD11/18 (80%), but the expression of gamma/delta TCR (6.5%), CD4 (10.6%), and CD21 (2.4%) was low. CD5lo cells were larger than CD5-high density (CD5hi) cells. Light and electron microscopy revealed numerous large cytoplasmic granules in CD5lo cells, especially after IL-2 stimulation, which was in contrast to CD5hi, in which intracytoplasmic granules were not frequently seen. After IL-2 stimulation, CD5lo cells had significantly stronger NK cytotoxicity than CD5hi cells. CD5lo cells had much higher mRNA levels for NKG2D, CD16, CD94, CD160, perforin, and granzyme than CD5hi. Following IL-2 stimulation, CD5lo cells had significantly higher mRNA levels of NKp30, NKp44, CD16, and CD94 than CD5hi cells. In addition, IL-2-stimulated, CD5lo-depleted PBL showed a loss of NK cytotoxicity. CD5lo cells also showed significantly lower antigen-specific cytotoxic T cell activity as compared with CD5hi cells. Taken together, the CD5lo subset in canine PBL is closely related to canine NK cells, and CD5lo can be used as a phenotypic marker for an IL-2-dependent canine NK cell enrichment.
Huang
Yi-Chun
YC
Animal Cancer Research Center, Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan.
Hung
Shao-Wen
SW
Jan
Tong-Rong
TR
Liao
Kuang-Wen
KW
Cheng
Chiung-Hsiang
CH
Wang
Yu-Shan
YS
Chu
Rea-Min
RM
D000818:Animals; D018956:CD5 Antigens / Q000378:metabolism*; D003601:Cytotoxicity Tests, Immunologic; D004285:Dogs; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression; D007371:Interferon-gamma / Q000378:metabolism; D019409:Interleukin-15 / Q000378:metabolism; D020382:Interleukin-18 / Q000378:metabolism; D015979:Killer Cells, Lymphokine-Activated / Q000276:immunology*; D007962:Leukocytes / Q000378:metabolism; D016131:Lymphocyte Subsets; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
D018956:CD5 Antigens; D019409:Interleukin-15; D020382:Interleukin-18; D012333:RNA, Messenger; D007371:Interferon-gamma