Download or read book Measles Virus [microform] : Immunoprecipitation and Monoclonal Antibody Production written by David John Paul Rafter and published by National Library of Canada. This book was released on 1981 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Antisera to the membrane (M) protein and to the nucleoprotein (NP) of measles virus, were prepared in rabbits. Each of the antisera was characterized by the immunoprecipitation technique and found to be monospecific. These monospecific antisera were used to determine, by indirect immunofluorescence, the cellular location of M-protein and NP during infection. The antiserum to M-protein stained the cytoplasm of Vero cells. The NP antiserum stained both the cytoplasm and nucleus. The NP was found to undergo breakdown in infected cells. This breakdown could be inhibited by aprotinin, a protease inhibitor specific for trypsin and chymotrypsin. As no protease function has been identified for the proteins of measles virus, it is believed that the proteolysis is a cellular function. The significance of proteolytic breakdown in the assembly of measles virus is discussed. Persons who receive inactivated measles vaccine and are subsequently exposed to wild type virus may experience atypical measles. It has been postulated that these individuals are susceptible to atypical measles because the inactivated vaccine fails to induce antibodies to the F-protein as detected by hemolysis-inhibition. Matched (acute and convalescent) serum samples were analyzed by the immunoprecipitation technique. Sera taken during the acute stage of the disease did not precipitate radiolabelled F-protein. Convalescent sera, which had been collected three weeks later, did precipitate the F-protein. The absence of antibodies to F confirms the earlier work obtained by hemolysis inhibition tests. These findings support the concept that atypical measles is the result of an absence of antibodies to F-protein. Once it was recognized that atypical measles appeared following the use of inactivated vaccines, an attenuated virus vaccine was introduced for widespread immunization programs. This vaccine was also used in "catch up" programs to reimmunize individuals who had previously received "killed" vaccine. The value of this "catch up" program was analyzed using matched serum samples obtained from children previously immunized with inactivated virus vaccine, who volunteered for reimmunization with the attenuated vaccine. Since in no case was reimmunization found to result in conversion to the production of antibody to F-protein, the attempt to irradicate atypical measles by this procedure should be re-evaluated. The monoclonal antibody technique was employed to obtain a series of monospecific antibodies to the measles virus proteins. In initial experiments 17 clones secreting antibody to the measles Lee strain were obtained. Of these, two clones have been established as stable cell lines. Both of these clones secrete antibody specific for the NP of the virus.