Serodiagnosis and Immunotherapy in Infectious Disease最新文献

Rubella reinfection, which can affect the developing foetus, is said to occur more frequently among people who have received rubella vaccine than among those whose rubella immunity is the result of a natural infection. We have compared the rate of increase in avidity of rubella-specific antibody in these two groups since differences either in the ability of the immune response to mature or in the rate at which it matures might be attributable to differences in antigen handling during the two modes of infection. Any differences in the type or the rate of maturation might then be responsible, at least in part, for the apparent increased susceptibility of vaccinees to reinfection. Although there was evidence to suggest that there was a slightly slower maturation rate at the later stages of the immune response among the vaccinees, the number of corresponding sera from cases of natural infection, taken several months after onset of symptoms, was insufficient to allow this to be demonstrated statistically. A larger, longitudinal study would be required to establish conclusively whether a true relationship between avidity maturation and an increase in reinfection rate among vaccinees exists.

Human cytomegalovirus (HCMV) is the most common cause of congenital and perinatal infections throughout the world. Primary infection with HCMV usually follows a benign course, but the virus remains latent or persistent in the host cell thereafter. Under immunosuppressive conditions, latent or persistent infection can be reactivated to produce a wide variety of clinical manifestations. Understanding the epidemiology of HCMV infection is a key element in development of strategies for prevention of infection. Definition of sites and mechanisms involved in the maintenance of latent or persistent HCMV infection and reactivation is also essential for a thorough understanding of the pathogenesis of HCMV infection. This mini review focuses on recent advances in the study of persistent infection and reactivation of HCMV. Although the actual sites of latency or persistence of HCMV infections are still controversial, peripheral blood mononuclear cells (PBMC) and endothelial cells appear to be the principal site of infection. Persistent infections caused by HCMV could be augmented by a decrease in major histocompatibility complex (MHC) expression as well as by virus-mediated immune dysfunction. It is also likely that specific cellular interactions as well as production of several cytokines are necessary for the reactivation of HCMV.

Sera from patients with schistosomiasis contain antibodies which react with keyhole limpet haemocyanin (KLH). This is due to carbohydrate epitopes shared by KLH and surface antigens of various Schistosoma species. Previous studies have used this cross-reactivity in enzyme-linked immunosorbent assay (ELISA) tests to distinguish between sera from acute and chronic cases in endemic areas. We describe a modification of the ELISA technique which distinguishes serologically between active schistosomiasis and normal sera. It has a sensitivity (88%) and specificity (94%) comparable with existing tests. If developed for routine clinical use, this test would be more useful in non-endemic areas than one which only detects acute cases.

The present paper describes the antibody pattern in the early stages of hepatitis C virus (HCV) infection and compares it with that obtained in chronic carriers. Samples were tested for anti-HCV from 470 consecutive patients admitted to gastroenterology services at three Havana hospitals, with serological and biochemical signs of non-A, non-B hepatitis, including those referred from three Havana blood banks because of a positive result in anti-HCV in pre-donation screening. Four anti-HCV enzyme immunoassay (EIA) systems and two supplementary assays were used for antibody detection. These results show that antibodies to viral core antigens are the first and commonest among Cuban patients infected with HCV, and generally, they can reveal the infection before the supplementary tests do. LiaTek HCV has proved to be a good tool for the confirmation of enzyme-linked immunosorbent assay (ELISA) positive samples.

Specific IgM antibodies in cerebrospinal fluid (CSF) from patients with leptospirosis were detected by enzyme-linked immunosorbent assay (ELISA). Thirty CSF samples from patients with the icterohaemorrhagic form of the disease (Weil's syndrome) with or without alterations in cell and protein contents were analysed. Thirty CSF samples obtained during anaesthesia from apparently healthy individuals with no clinical or epidemiological history of leptospirosis, six samples from patients with neurosyphilis and 109 samples from patients with meningitis of determined, non-leptospirotic aetiology were used as a control. The test showed 100% sensitivity, specificity and efficacy and showed advantages in terms of yield, rapidity and ease of execution, requiring only a single CSF sample and producing effective results in human leptospirosis.

A novel serological method dot-dye immunoassay (DIA) is described and the system is tested for the diagnosis of schistosomiasis mansoni. Sera of 32 chronic Schistosoma mansoni-infected patients and 12 non-infected individuals were simultaneously tested for the presence of IgG antibodies against soluble egg antigen (SEA) by DIA and enzyme-linked immunosorbent assay (ELISA). Optical density (OD) readings using 2,2′azino-bis 3-ethylbenzthiazoline-6-sulphonic acid (ARTS) substrate in ELISA (ODABTS) and dye conjugate in DIA (ODDYE) showed the coefficient of correlation of Pearson to be 0.91 (P < 0.0001). The DIA method has one step less than the ELISA technique, thus shortening the time of the test. The advantages of textile dyes as reaction indicators in the DIA method also include the absence of contact with potentially hazardous substrates, mostly employed in ELISA. Furthermore, colloidal dyes are less expensive than enzyme conjugates and substrates. The DIA method is a reliable and simple alternative for the serological diagnosis of Schistosoma mansoni infection.

Bacteria belonging to the genus Salmonella are a major cause of disease in both man and animals, with the pathogenesis of disease depending on the serovar of Salmonella and the host species involved. Infections with Salmonella bacteria generally result in the production of serum antibodies to ‘somatic’ (lipopolysaccharide), and in certain cases also to flagellar (‘H’) antigens. Serological tests, based on the detection of antibodies to Salmonella antigens can provide a valuable adjunct to established bacteriological techniques. In this article, the antibody response of humans and chickens to infection with key members of the genus Salmonella, is described.

An IgM capture enzyme immunoassay (IgM cap dot EIA) using a peroxidase-labelled Toxoplasma gondii antigen was standardized and assessed for the diagnosis of acute toxoplasmosis. This assay appeared to detect mostly IgM antibodies to Toxoplasma antigenic bands of 30, 27, 24, 22 and 18-17 kDa. In the study of serum samples (416) from patients with acute and chronic toxoplasmosis, from patients with unrelated diseases and from clinically healthy individuals, the IgM cap dot EIA showed diagnostic features similar to those of IgM capture enzyme-linked immunosorbent assay (ELISA) and IgM immunofluorescence test. Nevertheless, only this assay gave clear-cut results.