Membrane-bound or soluble truncated RT1.Aa rat class I major histocompatibility antigens induce specific alloimmunity.
Transfectants that express membrane-bound (MB) or secrete soluble truncated (TR) rat class I RT1.Aa major histocompatibility (MHC) antigens induce alloimmunity in vivo. The MB-RT1.Aa was produced by transfecting the full-length RT1.Aa cDNA, including the alpha 1, alpha 2, and alpha 3, transmembrane and intracellular domains. The TR-RT1.Aa cDNA insert included only the extracellular alpha 1, alpha 2, and alpha 3 domains; a stop codon was placed in front of the transmembrane domain. Following full-length sequencing, MB-RT1.Aa and TR-RT1.Aa cDNAs were translated in vitro into glycosylated MB-RT1.Aa (45 kDa) and TR-RT1.Aa (36 kDa) proteins, respectively. Each cDNA construct was individually subcloned into the pSG5 vector before transfection into Buffalo (BUF; RT1b) hepatoma cells. FACscan analysis with anti-RT1.Aa-specific R2/15S monoclonal antibody (MAb) confirmed surface expression of RT1.Aa molecules on the MB-RT1.Aa, but not on the TR-RT1.Aa, transfectants. In contrast, enzyme-linked immunoadsorbent assays documented the presence of soluble RT1.Aa molecules in supernates from cells transfected with the TR-RT1.Aa, but not from cells transfected with the MB-RT1.Aa, cDNA. Subcutaneous injection of MB-RT1.Aa or TR-RT1.Aa transfectants to BUF or Wistar Furth (WF; RT1u) rats induced accelerated rejection of ACI (RT1a) but not third-party Brown Norway (RT1n) heart allografts. Furthermore, supernates of TR-RT1.Aa, but not of MB-RT1.Aa, transfectants immunized WF hosts toward ACI hearts. Thus, both intact MB-RT1.Aa and soluble TR-RT1.Aa class I alloantigens induce potent sensitization against alloantigens.
Ghobrial
R
R
Division of Immunology and Organ Transplantation, University of Texas Medical School-Houston 77030, USA.
Hamashima
T
T
Kloc
M
M
Etkin
L
L
Stepkowski
S M
SM
Kahan
B D
BD
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000235:genetics; D015395:Histocompatibility Antigens Class I / Q000737:chemistry / Q000276:immunology*; D007518:Isoantibodies / Q000276:immunology; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology*; D008969:Molecular Sequence Data; D051381:Rats; D011912:Rats, Inbred ACI; D011915:Rats, Inbred BUF; D011920:Rats, Inbred WF; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D012995:Solubility; D014162:Transfection
D017931:DNA Primers; D018076:DNA, Complementary; D015395:Histocompatibility Antigens Class I; D007518:Isoantibodies; D008565:Membrane Proteins; D011994:Recombinant Proteins