Patients infected with human immunodeficiency virus (HIV) are highly susceptible to various bacterial infections, especially, Streptococcus pneumoniae. Encapsulated bacteria such as S. pneumoniae, Hemophilus influenzae and Klebsiella pneumoniae are known to be resistant to phagocytosis by neutrophils and macrophages unless cell-wall-specific antibodies are present. It is suggested, therefore, that the serum of HIV-infected patients is deficient in opsonic activity against these bacteria. In this study, we compared the serum opsonic activity of the patients with that of healthy normal persons by using the luminolenhanced chemiluminescence (CL) method. As CL assay is a very sensitive and reliable way for determining the opsonic activity of serum, the method can be used to quantify the opsonic activity of sera from HIV-infected patients.
