Immunologic recognition of influenza virus-infected cells. II. Expression of influenza A matrix protein on the infected cell surface and its role in recognition by cross-reactive cytotoxic T cells

Abstract

Two distinct subpopulations of cytotoxic T cells are generated in the primary or secondary response of mice to type A influenza viruses. One subpopulation is specific for the immunizing virus strain. The other subpopulation shows a high degree of cross-reactivity for heterologous type A virus of a different subtype. This report examines the possibility that distinct influenza virus antigens, expressed on the surface of the infected cell, are recognized by the different subpopulations of influenza-specific cytotoxic T cells. Data are presented which demonstrate that influenza A matrix protein, an internal virion antigen, is detectable on the surface of target cells infected with influenza A viruses of different subtypes. Since this viral antigen is type specific, i.e., serologically cross-reactive among all type A influenza viruses, it could serve as the target for cross-reactive cytotoxic T cells. To further examine the specificity of the two cytotoxic T-cell subpopulations, experiments were carried out by using the inhibitor of glycoprotein synthesis - 2-Deoxy-D-Glucose 2-DG. These experiments examine first the effect of 2-DG on the expression of influenza matrix protein and viral glycoprotein on the infected cell surface and second, the susceptibility of 2-DG-treated target cells to lysis by cytotoxic T cells. 2-DG inhibits the expression of the viral hemagglutinin glycoprotein on the cell surface but does not inhibit the expression of the nonglycosylated matrix protein. Furthermore, inhibition of glycoprotein synthesis in infected target cells abrogates the reactivity of infected target cells to lysis by virus strain-specific but not cross- reactive cytotoxic T cells. These findings suggest that the influenza glycoproteins (hemagglutinin and/or neuraminidase) and the nonglycosylated matrix protein are the targets for the virus strain- specific and cross-reactive cytotoxic T cells, respectively. These results are discussed in the light of available information on influenza virus structure and the biology of influenza infection and in terms of current models for cytotoxic T-cell recognition of virus-infected cells.

Specificity of cytotoxicity T cells directed to influenza virus hemagglutinin.

“…The present findings are therefore consistent with the concept that influenza hemagglutinin glycoprotein is a target antigen for the strainspecific CTL subpopulation stimulated by infectious influenza virus. Also consistent with this concept is our previous observation that nascent viral glycoprotein synthesis is required to render target cells susceptible to lysis by strain-specific CTLs (11). It is also evident from the present results showing that the high degree of cross-reactivity for target cells infected with type A influenza virus of unrelated subtypes, which is generated in response to infectious influenza virus (16,23,24) and is likewise mediated by a discrete subpopulation of cross-reactive CTLs (10,16,23) cannot be readily explained on the basis of reactivity to the influenza hemagglutinin.…”

“…It is also evident from the present results showing that the high degree of cross-reactivity for target cells infected with type A influenza virus of unrelated subtypes, which is generated in response to infectious influenza virus (16,23,24) and is likewise mediated by a discrete subpopulation of cross-reactive CTLs (10,16,23) cannot be readily explained on the basis of reactivity to the influenza hemagglutinin. Although CTLs directed to the influenza N have not as yet been directly demonstrated, it is reasonable to assume that such CTLs would have specificity characteristics comparable to those reported here for CTLs directed to influenza H. Thus, at present, the most likely candidate for the target antigen of the cross-reactive cytotoxic subpopulation is the internal virion antigen influenza matrix protein which is serologically cross-reactive among all type A influenza viruses and expressed on the surface of influenza-infected cells (11,28,29).…”

Generation of cytolytic T lymphocytes after reovirus infection: role of S1 gene.

“…For example, CTLs induced by recombinant clone 65 (which bears the type I S1 genome segment) gave 30% specific 51Cr release on type III-infected syngeneic targets at the highest effector/target ratio (33:1). This same degree of lysis was seen at the lowest effector/target ratio (4:1) on targets infected with 65 1 1 1 3 3 3 3 1 3 1 802 3 1 3 1 3 3 3 3 3 3 III 3 3 3 3 3 3 3 3 3 3 94 3 3 1 1 3 3 1 1 (7)(8)(9)(10). At least two populations of CTLs are generated from host lymphocytes stimulated by type A influenza.…”

“…The question of which viral antigens are recognized by CTLs has recently been addressed by use of influenza and vesicular stomatitis viruses (7)(8)(9)(10)(11)(12). The use of subtypes of influenza A virus has shown that the hemagglutinin is one of the proteins recognized by cytotoxic T cells (7)(8)(9)(10).…”

H‐2 Restriction Pattern of Secondary Influenza Virus‐immune Cytolytic T Cells

“…As shown in Table 1 Spleen lymphocytes of memory mice primed 3-12 weeks previously with IQ'' HAU (haemagglutiriiiting units) A/WSN virus by intraperitoneal injection were re-stimulated 1/ 1 vitro in bulk culture as described elsewhere (Braciale. 1977).…”