Induction of neutralizing antibody in mice against poliovirus type II with monoclonal anti-idiotypic antibody.

Syngeneic monoclonal anti-idiotope antibody Ab2,2-17C3SCC was raised against an idiotope on a protective monoclonal antibody with specificity for poliovirus type II. Ab2,2-17C3SCC detects a paratope-related interspecies IdX. Ab2,2-17C3SCC purified from supernatant fluids of hybridoma cells by protein A-Sepharose was injected into 4- to 6-wk-old BALB/c mice. The sera of the mice were screened for the expression of antibodies bearing the corresponding idiotope. Immunization of mice with Ab2,2-17C3SCC induced antibodies of complementary specificity. Furthermore, micro VN tests suggest that Ab2,2-17C3SCC can substitute for antigen in the induction of anti-polio neutralizing antibodies, and hence can function as a monoclonal anti-idiotypic vaccine

Control of feline leukaemia virus.

Feline leukaemia virus (FeLV) usually occurs in its natural species, the domestic cat. FeLV is also important to human individuals as a comparative model, as it may cause a variety of diseases, some malignant and some benign, such as immunosuppression, which bears a resemblance to AIDS (acquired immune deficiency syndrome) in man. FeLV is transmitted among cats by contagion. The main sources of infection are persistently infected carrier cats which continuously excrete virus. Dissemination of FeLV among cats may be prevented by identifying infected carrier cats and removing them from contact with non-infected cats. Removal programmes using indirect immunofluorescence antibody tests were applied successfully in The Netherlands. The proportion of FeLV-positive cats decreased from 9% in 1974 to approximately 3% in 1985 during such a programme. The results of a removal programme carried out in a catbreeders' society were even better: the incidence of cats positive for FeLV decreased from 11% in 1974 to less than 2% within 4 years. None of the cats tested in this society has been found to be positive for FeLV since 1984. Besides removal programmes, other methods of control, such as pre-exposure treatment, were developed to prevent the spread of FeLV. We attempted to protect kittens against oronasal infection with FeLV by treatment with virus-neutralizing (VN) monoclonal antibodies (MoAbs) directed against an epitope on the viral glycoprotein gp70. However, no protection was achieved. It is unlikely that the amount of VN antibodies, the mode and route of their application or the infectious dose of FeLV used can account for this failure. Other possible explanations for the lack of protective effect are that (i) the restricted epitope specificity of the MoAb preparation used may have led to selection of neutralization-resistant virus mutants, or (ii) other mechanisms than virus neutralization (complement-mediated lysis, antibody-dependent cell cytotoxicity), that may be involved in protection, function less efficiently with MoAb. However, in the light of our finding that an early anti-idiotypic response is observed in all cats following administration of the MoAb preparation, the rapid clearance of anti-FeLV MoAb from the circulation is a more likely explanation. Efforts were further made to develop a vaccine for controlling FeLV infection. The immunostimulating complex vaccine (FeLV-ISCOM vaccine), a subunit vaccine in which FeLV gp70 is presented in a particular manner, looks promising. The protective effect of FeLV-IS

Maintenance of immunological memory: A role for CD5+ B cells?

How memory is retained is an immunological mystery. One possibility, argued here by Fons UytdeHaag and colleagues, is that memory is imprinted in the somatically-mutated Ig expressed by certain CD5+ B cells. The theory proposes that the Ig expressed by this self-renewing population acts as surrogate antigen, selecting and stimulating emerging antigen-specific lymphocytes

Rabies virus cross-reactive murine T cell clones: analysis of helper and delayed-type hypersensitivity function.

Three T cell clones derived from rabies virus-immunized BALB/c mice were analysed for specificity and function. The clones proved to be broadly cross-reactive by responding to different rabies virus isolates (PM, ERA, CVS, HEP) and other representatives of the genus Lyssavirus, like the Duvenhage-6 (DUV6) and Mokola (MOK) viruses. The clones detected three different epitopes: an epitope expressed on the matrix protein (M) shared by PM, HEP, MOK and DUV6 viruses (clone AA8), an epitope expressed on the M-protein shared by PM, ERA, CVS, HEP and MOK viruses (clone 35A) and finally an epitope expressed on the glycoprotein (G-protein) shared by PM, ERA, CVS, HEP and MOK viruses (clone BG2). Antigen recognition of all clones proved to be MHC-restricted and they all displayed the CD4+ CD8- phenotype. Intravenous inoculation of the T cells in syngeneic mice, which had been injected intracutaneously in the ear with HEP virus, resulted in a localized DTH reaction characteristic for TH1 cells. In vitro, the clones were able to provide help to rabies virus-primed B cells, resulting in the production of virus-specific antibodies directed against all the four structural proteins of rabies virus. Further analysis of this antibody response revealed that part of it was directed against antigenic determinants of the G-protein which induce virus neutralizing antibody

Induction and characterization of monoclonal anti-idiotypic antibodies reactive with idiotopes of canine parvovirus neutralizing monoclonal antibodies.

Monoclonal anti-idiotypic (anti-Id) antibodies (Ab2) were generated against idiotypes (Id) of canine parvovirus (CPV) specific monoclonal antibodies (MoAbs). The binding of most of these anti-Id antibodies to their corresponding Id could be inhibited by antigen, thus classifying these anti-Id antibodies as Ab2 gamma or Ab2 beta. By inhibiting experiments it was shown that these anti-Id antibodies did not recognize interspecies cross-

Purification of infectious canine parvovirus from cell culture by affinity chromatography with monoclonal antibodies.

Immuno affinity chromatography with virus neutralizing monoclonal antibodies, directed to the haemagglutinating protein of canine parvovirus (CPV) was used to purify and concentrate CPV from infected cell culture. The procedure was monitored by testing the respective fractions in an infectivity titration system, in an ELISA, in a haemagglutination assay and by negative contrast electron microscopy to quantify CPV or CPV antigen. The degree of purification was further estimated by testing the fractions for total protein content in a colorimetric method, for bovine serum albumin content in an ELISA and by SDS-PAGE. Over 99% of the contaminating proteins proved to be removed, and 20% or 70-90% of infectious CPV or CPV antigen, respectively, was recovered

Intracellular processing and presentation of T cell epitopes, expressed by recombinant Escherichia coli and Salmonella typhimurium, to human T cells

Vaccines based on recombinant attenuated bacteria represent a potentially safe and effective immunization strategy. A carrier system was developed to analyze in vitro whether foreign T cell epitopes, inserted in the outer membrane protein PhoE of Escherichia coli and expressed by recombinant bacteria, are efficiently processed and presente

The use of enzyme-linked immunosorbent assay systems for the serology and antigen detection in parvovirus, coronavirus and rotavirus infections in dogs in The Netherlands.

Complex trapping blocking (CTB) enzyme-linked immunosorbent assays (ELISAs) and indirect ELISAs for the detection of antibodies to canine parvovirus (CPV), canine coronavirus (CCV) and rotavirus in sera of dogs were established. Double antibody sandwich ELISAs for the detection of CPV-, CCV- and rotavirus antigens in fecal samples were also developed. Both the serological and antigen-detection ELISAs were used to screen samples from dogs in The Netherlands, with or without a history of acute diarrhea. It was shown that the results of the respective serological ELISAs correlated well and that CPV was the major cause of virus-induced acute diarrhea in dogs in The Netherlands

Analysis of the antigen- and mitogen-induced differentiation of B lymphocytes from asymptomatic human immunodeficiency virus-seropositive male homosexuals. Discrepancy between T cell-dependent and T cell-independent activation.

Five asymptomatic human immunodeficiency virus (HIV)-seropositive ; male homosexuals were immunized with the recall antigens tetanus toxoid (TT) and the three types of poliovirus present in diphtheria, tetanus, and polio vaccine. Four weeks after immunization, the in vivo response to booster immunization, the in vitro pokeweed mitogen (PWM)-induced IgG secretion, and the in vitro T cell-dependent and T cell-independent antigen-induced antibody response were assayed. Increase in serum antibody titer to TT and polioviru