Polymorphonuclear leukocyte function in HIV-1-infected chimpanzees

Measurement of phagocytosis and oxidative burst of canine neutrophils: high variation in healthy dogs

Quantitative analysis of phagocytosis and oxidative burst in canine polymorphonuclear (PMN) cells was performed by flow cytometry techniques. Different concentrations of phorbol myristate acetate (PMA) were used to modulate PMN phagocytosis. A low concentration of PMA (3 nmol) resulted in increased phagocytic activity of canine PMN, which could not be enhanced by higher dosages. Experiments with a reference cell population showed high losses of PMN, most probably by adherence to plastic material. It was possible to avoid this loss by layering all ingredients on cushions of Histopaque. However, Histopaque had a negative influence on the phagocytic activity of canine PMN. The use of PMA led to a dosage-dependent increase in the oxidative burst measured by the production of reactive oxygen species (ROS). Cushions of Histopaque were used to avoid cell loss. There was no negative influence of Histopaque on ROS formation. Storage of canine PMN for 24 h at room temperature had no negative influence on phagocytosis or oxidative burst measurements. Variations in the ROS assays conducted by two different examiners could be eliminated by use of a Histopaque-cushion.

Zygomycosis and HIV infection

The severe immunosuppression associated with HIV infection increases susceptibility to opportunistic fungi. We describe a primary gangrenous cutaneous infection caused by Rhizopus arrhizus in an HIV-infected intravenous narcotic user. In addition, we review nine reported cases of zygomycosis in HIV-infected patients and discuss the frequency and outcome of zygomycosis in HIV infection. Eight of 10 patients were intravenous drug users. Cutaneous infection occurred in four patients. Another case was associated with drug-induced neutropenia. With treatment, 60% of the patients recovered. HIV-induced immunosuppression rarely predisposes to zygomycosis except in intravenous drug users or persons with other risk factors for this fungal infection.

Highly attenuated poxviruses induce functional priming of neutrophils in vitro

Highly attenuated poxvirus samples were used to examine the influence of potential poxvirus expression vector systems on neutrophil function. Exposure to the viruses alters the number of membrane bound complement-and Fc gamma-receptors and led to functional priming of neutrophils to subsequent stimuli.

Oxidative imbalance in HIV infected patients

We present an outline of the complex interplay of oxidants and antioxidants in infectious diseases in general, and in particular with reference to the HIV infection, and subsequent opportunistic infections. Viral and opportunistic infections may directly or indirectly cause an imbalance in prooxidant/antioxidant mechanisms and result in generation of increased steady state concentrations of reactive oxidants. In HIV patients a prooxidant state could lead to a self-perpetuation of infection via stimulated expression of genes carrying the virus genome, and subsequently to immunosuppression, and promotion of initiated cells to neoplastic growth.

Role of polymorphonuclear leukocytes in infection by retroviruses with emphasis on the human immunodeficiency virus

Neutrophil function is an integral part of the host defense against multiple pathogens. Through phagocytosis and production of toxic substances, these short lived cells aid in the effective elimination of invading microorganisms such as bacterial and fungal targets. Viral infections, and in particular those of the retroviral type, appear to suppress the immune response through direct cytotoxic destruction of immune cells or alteration of the biochemical interactions that are essential for eradicating the foreign agent. In this report, we describe abnormalities of neutrophil number and function consequent to HIV and other retroviral infections. A myriad of mechanisms, either alone or in concert may explain the underlying aberrations.