CD3−NK1.1+ cells aid in the early induction of a Th1 response to an attaching and effacing enteric pathogen

Extracellular attaching and effacing (A/E) pathogens including pathogenic Escherichia coli colonize the host gut causing diarrhea and inflammation. Although much is known regarding the pathogenesis of A/E bacteria, there remains an incomplete understanding of host immune responses to these microbes. NK cells are an important source of IFN‐γ and are essential for early innate responses to viral pathogens; however, their role during extracellular bacterial infections is still largely unexplored. We studied the host response to the murine A/E pathogen Citrobacter rodentium to investigate NK‐cell function during infection. NK1.1⁺ cell depletions and analysis of colonic intestinal inflammation following Citrobacter infection demonstrated that CD3^?NK1.1⁺ cells play an important role in the initial clearance of C. rodentium, as evidenced by higher bacterial load, intestinal pathology, and crypt hyperplasia at the peak of inflammation in depleted mice. Loss of CD3^?NK1.1⁺ cells resulted in lower colonic IFN‐γ, TNF‐α, and IL‐12, and a delay in homing of IFN‐γ⁺CD4⁺ T cells to the gut. Loss of this response resulted in lower anti‐C. rodentium IgG in NK1.1‐depleted mice. These data establish that CD3^?NK1.1⁺ cells are critical for inducing an early Th1 response involved in clearance of a pathogen that is restricted to the gastrointestinal tract.     

Cell-Surface-Marker Phenotyping in Patients with Leukemic Non-Hodgkin Lymphomas (NHL) of Low and Intermediate Malignancy

Certain markers for B lymphocytes (SIg, EAIgG, EAIgMC3b, EAIgMC3d, M-R) and T lymphocytes (E-R, EAIgG, EAIgM) were applied in order to characterize circulating neoplastic cells in non-Hodgkin lymphomas (NHL) of low and intermediate malignancy. In all cases, the diagnoses were based on the histological examination of lymph nodes, bone marrow, or skin biopsies. According to the Kiel classification, the diagnoses were as follows: chronic lymphocytic leukemia (CLL) n = 145. Immunocytoma (Ic) n = 39. Centrocytic (Cc) and centroblastic/centrocytic lymphoma (Cb/Cc) n = 17. Hairy-cell leukemia (HCL) n = 10. Prolymphocytic leukemia (PLL) n = 6 and Sézary's syndrome n = 3.In only 8 of the 220 cases did the leukemia cells show T characteristics. In leukemic B-cell lymphoma, a uniform phenotype was observed for B-CLL, characterized by a weak SIgm staining with or without SIgD, the presence of C₃d-receptors and a high percentage of M-R. This phenotype was also detected in one third of the cases of immunocytoma. The cells of BPLL and leukemic CC and CB/CC were characterized by a stronger SIg staining, a variable formation of complement receptors and, in most cases, absence of M-R. In all cases of B-cell lymphoma, the monoclonality of the cell proliferation could be confirmed by the restriction to a single L-chain type. This also applies to the 10 cases of HCL, although in the majority of these cases, several heavy-chain classes could be detected at the malignant cells.     

Physiological organization of immune response based on the homeostatic mechanism of matrix reprogramming: Implication in tumor and biotechnology

It is accepted that the immune system responds to pathogens with activation of antigen-independent innate and antigen-dependent adaptive immunity. However many immune events do not fit or are even inconsistent with this notion. We developed a new homeostatic model of the immune response. This model consists of four units: a sensor, a regulator, an effector and a rehabilitator. The sensor, macrophages or lymphocytes, recognize pathogenic cells and generate alarm signals. The regulator, antigen-presenting cells, Тregs and myeloid-derived suppressor cells, evaluate the signals and together with sensor cells program the effector. The effector, programmed macrophages and lymphocytes, eliminate the pathogenic cells. The rehabilitator, M2 macrophages, restrict inflammation, provide angiogenesis and reparation of tissue damage, and restore the homeostasis. We suggest the terms “immune matrix” for a biological template of immune responses to pathogens and “matrix reprogramming” for the interdependent reprogramming of different cells in the matrix. In an adequate immune response, the matrix forms a negative feedback mechanism to support the homeostasis. We defined the cellular and phenotypic composition of a tumor immune matrix. A tumor reprograms the homeostatic negative feedback mechanism of matrix into a pathogenic positive feedback mechanism. M2 macrophages play a key role in this transformation. Therefore, macrophages are an attractive target for biotechnology. Based on our hypotheses, we are developing a cell biotechnology method for creation of macrophages with a stable antitumor phenotype. We have shown that such macrophages almost doubled the survival time of mice with tumor.