Characterization of effector functions of human peptide-specific CD4+ T-cell clones for an intracellular pathogen

CD4+ T cells are believed to play a dominant role in human defenses against Mycobacterium tuberculosis through production of interferon (IFN)-gamma, cytolytic T-cell (CTL) activity, and inhibition of intracellular mycobacterial growth. Most functional studies of CD4+ cells have used bulk T-cells that recognize crude mycobacterial antigens, and the functional capacity of individual human T cells is not well defined. We studied the functional capacity of human CD4+ T-cell clones that recognize a specific mycobacterial peptide. Clone B9 produced high concentrations of IFN-gamma and exhibited potent CTL activity, whereas clone D3 produced IFN-gamma but showed poor CTL activity. The CTL activity of clone B9 was inhibited by SrCl(2) and concanamycin A but not by anti-Fas antibodies. Clone B9 also reduced the mycobacterial burden in dendritic cells by more than 90%, and this antimycobacterial activity was inhibited by SrCl(2) and concanamycin A. We conclude that: (1) individual human peptide-specific CD4+ T-cell clones have differential capacity to produce Th1 cytokines and to lyse M tuberculosis-infected target cells; and (2) both granulysin and perforin contribute to the capacity of human CD4+ T-cells to lyse infected targets and to inhibit intracellular mycobacterial growth.     

Fatal alveolar hemorrhage and Abciximab (ReoProTM) therapy for acute myocardial infarction

We describe two cases of diffuse alveolar hemorrhage and development of ARDS in patients who underwent percutaneous transluminal coronary angioplasty (PTCA) with stenting in whom Abciximab (ReoPro^TM) was used in combination with other agents interfering with the hemostatic mechanism. The development of pulmonary infiltrates, associated with a fall in hemoglobin after the administration of Abciximab, should strongly suggest the possibility of diffuse alveolar hemorrhage. Physicians should be aware of the possible association between the use of Abciximab and the development of alveolar hemorrhage. Cathet. Cardiovasc. Diagn. 44:313–316, 1998. © 1998 Wiley-Liss, Inc.