Development of a monoclonal antibody specific for the gamma chain of the T-cell antigen receptor using an open reading frame expression vector

Gamma/delta T cell antigen receptors expressed on tumor-infiltrating lymphocytes from patients with solid tumors

The expression of gamma/delta T cell antigen receptors (TcR) in T cell lines or clones derived from tumor-infiltrating lymphocytes (TIL) from patients with solid tumors was investigated. gamma/delta TcR T cell lines were derived from TIL from patients with Wilms tumor, sarcoma or metastatic melanoma by stimulation with autologous tumor cells alone and recombinant interleukin 2 and they exhibited nonspecific cytotoxicity against autologous and allogeneic tumor cells, or cells of the K562 or the MEL21 tumor cell lines. Two T cell lines were derived from a patient with Wilms tumor. One of them expressed a non-disulfide-linked gamma/delta TcR using the 60-kDa gamma chain, whereas, the other expressed a disulfide-linked gamma/delta TcR. A T cell line was derived from a patient with sarcoma and expressed a disulfide-linked gamma/delta TcR, whereas, a T cell line derived from a patient with melanoma expressed a non-disulfide-linked gamma chain of 62 kDa. Several T cell clones were developed from patients with metastatic melanoma or Wilms tumor and expressed either disulfide- or non-disulfide-linked gamma/delta TcR. Northern analysis of RNA from certain of these clones revealed a full-length gamma chain transcript, whereas, the alpha or beta chain transcripts were either absent or truncated. These T cell clones exhibited nonspecific cytotoxicity. Both disulfide- and non-disulfide-linked TIL T cell lines and clones expressed the delta TCS1 determinant. gamma/delta TcR+ cells in freshly prepared TIL from these patients were present in low proportions (less than 5%) and their delta TCS1/delta 1 ratios were within the range observed in the peripheral blood of normal donors. These results demonstrate that both disulfide- and non-disulfide-linked gamma/delta TcR are expressed on T cell lines and clones derived from TIL from solid tumors. Non-disulfide-linked gamma/delta TcR using the 56-66-kDa gamma chain are frequently found on TIL-derived T cell lines and clones. These 56-66-kDa gamma chains are rarely expressed on T cell lines or clones derived from peripheral blood lymphocytes of normal donors.

Immunoglobulin Fc binding activity is associated with the mouse hepatitis virus E2 peplomer protein

Antigenic variation among murine coronaviruses is associated primarily with the surface peplomer protein E2 (180,000 Da). E2 is responsible for attachment of the virus to the host cell, MHV-induced cell fusion, and eliciting neutralizing antibody. We report here the molecular mimicry between E2 and Fc gamma receptor (Fc gamma R). Molecular mimicry between E2 and Fc gamma R may allow the escape of virus-infected cells from destruction by immunological mechanisms. Rabbit IgG, monoclonal rat IgG1 and IgG2b, monoclonal mouse IgG2a and IgG2b, and the rat anti-mouse Fc gamma R monoclonal antibody 2.4G2 immunoprecipitated from MHV-JHM-infected cells a polypeptide with a molecular mass identical to that immunoprecipitated by anti-E2 antibodies. F(ab')2 fragments of rabbit IgG did not immunoprecipitate any proteins from MHV-infected cells. All of these antibodies did not immunoprecipitate any proteins from uninfected cells. The anti-mouse Fc gamma R monoclonal antibody 2.4G2 immunoprecipitated from MHV-JHM-, MHV-3-, or MHV-A59-infected L-2 cells and 17CL-1 cells, or MHV-JHM-infected cultures of neonatal BALB/c brain cells, a protein with a molecular weight identical to that of MHV-JHM E2. The anti-Fc gamma R monoclonal antibody did not immunoprecipitate any proteins from uninfected cells. Furthermore, the 2.4G2 monoclonal antibody (mab), unrelated rat and mouse monoclonal antibodies, and a goat antiserum against E2, but not normal goat serum, immunoprecipitated a 75,000- to 77,000-Da molecule from uninfected WEHI-3 cells, a Fc gamma R bearing cell line. Several lines of evidence demonstrated that the protein immunoprecipitated by the anti-Fc gamma R mab from MHV-JHM-infected cells is the E2 glycoprotein: (1) Partial proteolytic maps obtained by Staphylococcus aureus V-8 protease treatment of the 180,000-Da proteins immunoprecipitated by the anti Fc gamma R mab and the anti-E2 mab were identical. (2) Sequential immunoprecipitation experiments from MHV-JHM-infected cells revealed that the same polypeptide chain was recognized by the anti-E2 mab and by the anti-Fc gamma R mab 2.4G2, (3) Actinomycin D did not influence the induction and expression of the 180,000-Da polypeptide chain that was immunoprecipitated by the anti-Fc gamma R mab, demonstrating that this protein is of viral origin.

Disulfide-linked gamma delta T cell antigen receptors expressed on T cells derived from patients with primary immunodeficiency disorders

T cell lines or clones from two patients, one with a partial DiGeorge syndrome and one with severe common variable immunodeficiency expressed disulfide-linked gamma delta T cell antigen receptor (TCR) comprised of a gamma-chain polypeptide of 40-43 kD, and a delta-chain polypeptide of 37-40 kD. This gamma delta TCR appears to be similar to that found on T cell clones, and lines derived from peripheral blood lymphocytes from normal donors. Previous studies have shown that T cell lines derived from the peripheral blood of patients with immunodeficiency disorders express non-disulfide-linked gamma delta TCR. In contrast to the latter and coincident with findings in the present study, the vast majority of T cell lines and clones derived from the peripheral blood of normal donors express disulfide-linked gamma delta TCR.