Detection of cells producing surface antigen-specific antibody to influenza viruses

Simple scaling laws for influenza A rise time, duration, and severity

Simple scaling laws are developed for the severity and characteristic time scales of influenza A infection in man. The scaling laws are based on a model of the infection described by six coupled ordinary differential equations that describe the time courses of the numbers of infectious viral particles, activated cytotoxic T-lymphocytes, interferon molecules, infected cells, uninfected cells, and the subset of uninfected cells that are protected by interferon from viral infection. Computer simulations show that the disease can be regarded approximately as a two-stage process. In the first stage, the growth in the number of infected cells is determined primarily by the interferon-enhanced limitation in the available number of target cells. In the second stage, the bulk of the duration of the infection is determined mainly by the destruction of the infected cells by the cytotoxic T-lymphocytes. The severity and characteristic times of the infection are found to depend simply on the logarithm of the initial number of viruses.

Evaluation of methods for chemically coupling foot-and-mouth disease virus to sheep red blood cells for immunological assays

Six methods of chemically coupling proteins to red blood cells were evaluated for their effectiveness in coupling foot-and-mouth disease virus (FMDV) to sheep red blood cells. The coupling agents tested were potassium periodate, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (ECDI), chromium chloride, glutaraldehyde, bis-diazotized benzidine (BDB) and N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP). Of these, only the coupling methods using BDB and SPDP resulted in virus-red cell complexes that reacted with FMDV antiserum in passive hemagglutination and passive immune hemolysis assays. The BDB and SPDP methods were studied further to determine optimal coupling conditions, the kinetics of coupling and the effects of chemical couplers on viral integrity. Only the FMDV-red cell complexes formed with SPDP were suitable targets for detecting FMDV antibody producing lymphocytes in a hemolytic plaque assay.

Immune response to hepatitis B surface antigen: enhancement by prior injection of antibodies to the idiotype

Anti-idiotype reagents that recognize a common idiotype associated with the combining site of antibodies to hepatitis B surface antigen (anti-HBs) were used to manipulate the immune response to hepatitis B surface antigen in BALB/c mice. The injection of antibodies to the idiotype before antigenic stimulation resulted in an increase in the number of cells secreting immunoglobulin M antibodies to hepatitis B surface antigen. Anti-HBs-secreting cells were also induced by administration of antibodies to the idiotype without subsequent antigen exposure. These findings indicate that the immune response to hepatitis B surface antigen in mice is regulated through an idiotype-anti-idiotype network.

Augmentation of the antibody forming cell response to neuraminidase-treated cells by myxoviruses

Following the inoculation of Newcastle Disease virus, Sendai virus and influenza virus CBA mice made a specific plaque-forming cell response to virus-treated sheep red blood cells but not to virus-treated L1210 cells. This non-specific response to virus-treated L1210 could be exactly reproduced by treatment of L1210 with bacterial neuraminidase. Neuraminidase-treated cells from eight of nine vertebrates including chickens and syngeneic mice also registered plaques. Inoculations of the above viruses were considered to have evoked separate antibody forming cell responses to viral antigens, foreign cell components in the virus inoculum and to neuraminidase revealed cell membrance antigens.

Induction of cytolytic T- and B-cell responses against influenza virus infections

Inoculation of mice with live influenza virus results in the induction of cytotoxic thymus-derived (T) lymphocytes and of bone marrow-derived (B) cells producing antiviral antibodies. An assay system was developed to evaluate both types of immune responses on a cellular basis within the same lymphocyte pool with no need to separate out the different effector cell classes. The test system represented a modification of the 51Cr-release assay. T-cell activity was measured exclusively in the absence of active complement using targets that were compatible for determinants encoded by the mouse major histocompatibility gene complex, H-2. H-2-different and even xenogeneic target cells were lysed in the presence of either non-inactivated fetal calf serum or normal rabbit serum as a complement source. Cytotoxicity was mediated in the latter case by direct interaction of B-cell-produced immunoglobulin directed to viral antigens expressed by the target cell and complement. Antibody-dependent cell-mediated cytotoxicity mechanisms did not contribute to cytotoxicity in the test system described. It was demontrated that the cytolytic B-cell responses of one particular strain of mice (BALB/c) against different influenza A viruses were restricted to the immunizing virus on the effector cell level. In another strain of mice (C3H), B cells revealed a broad cross-reactive response resembling that of killer T cells.

Regional T- and B-cell responses in influenza-infected ferrets

Ferrets were infected with A/Port Chalmers/72 influenza virus and the T- and B-cell responses in the spleen, in lymph nodes draining the upper and lower respiratory tract, and in lung washings were examined in vitro. Lymphocyte responses were measured by using a hemolytic plaque assay for B cells and a proliferation assay for T cells. Virus and antibody levels were measured in respiratory tract washings, and antibody titers were measured in sera from infected animals. Individual B cells secreting specific antibody to A/Port Chalmers/72 virus were detected in regional lymph node and spleen preparations as early as 3 days and as late as 43 days after infection. T-cell assays showed an in vitro response of lymph node cells to A/Port Chalmers/73 virus from day 6 to day 43. Virus was isolated from the respiratory tract up to 7 days after infection. Serum hemagglutination-inhibiting antibody was first detectable on day 6, with maximum titers reached by day 10. These results demonstrated that antibody production and a cellular immune responses were detectable at regional sites at a time when virus was still present and before serum antibody was measured.