Limited effect of recombinant porcine interleukin-12 on porcine lymphocytes due to a low level of IL-12 beta2 receptor.
The cytokine interleukin-12 (IL-12) is a key molecule in the regulation of CD4 + T cell development and specifically potentiates T helper 1 responses in mouse and man. However, biological effects mediated by IL-12 have not been well defined in pigs. Herein, recombinant porcine IL-12 (rPoIL-12) was expressed in a swine poxvirus system as a biologically active heterodimer and used to stimulate bovine or swine lymphoblast cells. After 3 days of incubation, only bovine blasts were responsive to the rPoIL-12 treatment as monitored by cell proliferation in several independent trials. Similarly, i.m. administration of rPoIL-12 in the hind leg of 3-week-old pigs indicated a reduction in the number of interferon-gamma (IFN-gamma) producing lymphocytes isolated from inguinal lymph nodes. The porcine IL-12R beta2 (IL-12Rbeta2) sequence was cloned and results generated by reverse transcriptase polymerase chain reaction (RT-PCR) demonstrated that the expression of IL-12R on porcine blasts as measured by the relative levels of IL-12Rbeta2 mRNA was less than that in bovine blasts and are in agreement with the reduced proliferation response of swine blast cells to rPoIL-12 treatment. Real time PCR analysis demonstrated that after PBMC stimulation, bovine blasts had an 11-fold increase in IL-12Rbeta2 mRNA levels while porcine blasts had almost no change. These data support a mechanism for IL-12 stimulation in swine inconsistent with that observed in conventional models.
Solano-Aguilar
G I
GI
Nutrient Requirement and Functions Laboratory, BHNRC-ARS-USDA, 10300 Baltimore Avenue, Building 307, Room 228, Beltsville, MD 20705, USA. solano-aguilar@ba.ars.usda.gov
Zarlenga
D
D
Beshah
E
E
Vengroski
K
K
Gasbarre
L
L
Junker
D
D
Cochran
M
M
Weston
C
C
Valencia
D
D
Chiang
C
C
Dawson
H
H
Urban
J F
JF
Lunney
J K
JK
D000595:Amino Acid Sequence; D000818:Animals; D001681:Biological Assay; D015153:Blotting, Western; D002417:Cattle; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis / Q000096:biosynthesis; D018664:Interleukin-12 / Q000008:administration & dosage / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D021122:Protein Subunits; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D018123:Receptors, Interleukin / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D053707:Receptors, Interleukin-12; D017386:Sequence Homology, Amino Acid; D018148:Suipoxvirus / Q000235:genetics; D013552:Swine / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
C508439:IL12RB2 protein, human; C508443:Il12rb2 protein, mouse; D021122:Protein Subunits; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D053707:Receptors, Interleukin-12; D018664:Interleukin-12; D007371:Interferon-gamma