Some factors influencing the microtest method for neutralizing antibodies to the virus for neutralizing antibodies to the virus of infectious bovine rhinotracheitis.
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Animals↗
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Results for “Antibodies, Neutralizing”
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An improved method for determining neutralizing antibody against lymphocytic choriomeningitis virus in human sera.
Human antibody neutralizing lymphocytic choriomeningitis virus is most reliably determined in mice as assay hosts. Whereas the previously recommended procedure yielding a neutralization index requires much serum, the method described here uses only 0.1 ml. An equal mixture of virus and serum is incubated and residual infectivity is titrated intracerebrally in mice. The neutralizing activity is given by the ratio of virus surviving after incubation with control serum and with the test serum respectively. This ratio is called the neutralization factor.
Animals↗
Distinct modes of evolution drive HIV escape from two broadly neutralizing antibodies.
Broadly neutralizing antibodies (bNAbs) show promise for HIV treatment and prevention, but are vulnerable to resistance evolution. Comprehensively understanding in vivo viral escape from individual bNAbs is necessary to design bNAb combinations that will provide durable responses. We characterize viral escape from two such bNAbs, 10-1074 and 3BNC117, using deep, longitudinal sequencing of full length HIV envelope (env) genes from study participants treated with bNAb monotherapy. Improved sequencing depth and computational evolutionary analyses permit us to identify in vivo routes and parallelism underlying HIV escape from each bNAb, providing new insights into this evolutionary process: 10-1074 escape is restricted to a small number of previously documented pathways, but these escape mutations 1) pre-exist in intra-host viral populations before therapy, 2) are not all equally preferred, and 3) emerge with a high degree of genetic parallelism within and across viral populations. In contrast, 3BNC117 escape follows background-specific patterns in which specific escape mutations present in one population rarely emerge or spread in other populations, but often still exhibit parallel evolutionary responses within their host. That bNAbs elicit starkly different in vivo escape profiles depending on their Env target exposes the limitations of generalizing escape patterns across therapies and highlights the substantial challenges in predicting a viral population's bNAb susceptibility from genetic diversity alone.
Journal Article↗
Neutralizing antibody responses to varicella-zoster virus.
Neutralization of varicella-zoster (V-Z) virus by human sera and immune rhesus monkey sera was enhanced by fresh guinea pig complement. There was no marked difference in the degree to which complement enhanced neutralization by sera from current V-Z virus infections and sera from long-past varicella infections. Immunoglobulin G neutralizing antibody in sera from varicella cases was enhanced by complement to a slightly higher degree than was immunoglobulin M (IgM) antibody, and immunoglobulin G neutralizing antibody in immune monkey sera was enhanced to a much greater degree than was IgM antibody. There was a rapid decline in the complement requirement of IgM neutralizing antibodies over the course of immunization of the rhesus monkeys. V-Z neutralizing antibody titers in the presence of complement were higher than complement-fixing titers of the same sera in all groups of individuals studied. IgM neutralizing antibody for V-Z virus was demonstrable in all cases of varicella but in only 1 of 22 zoster cases, and V-Z IgM neutralizing antibody was not detectable in primary herpes simplex virus infections in which heterotypic antibody titer rises occurred to V-Z virus. Complement-fixing antibody for V-Z virus was absent in 19S serum fractions which contained IgM neutralizing antibody for the virus.
Animals↗
Comparison between two antibody populations in the EBV system: anti-MA versus neutralizing antibody activity.
EBV-neutralizing antibody titers were determined in 11 sera derived from African Burkitt lymphoma or nasopharyngeal carcinoma patients and in the corresponding serum fractions retained above XM 100 Diaflo membranes after low pH treatment, and after recombination of the retained and passed fractions by neutralization of the acidified samples. They were compared with the corresponding antimembrane antigen (MA) titers in seven of the same sera. While all sera tested showed substantial increase of the anti-MA activity in the retained fraction, resulting in a significantly increased mean titer, EBV neutralizing activity did not change at all after identical treatment or changed only in a random fashion, resulting in stable mean titers. It is suggested that anti-MA and neutralizing antibodies are directed against at least partly different antigens on the virus.
Animals↗
Antibody class and complement requirement of neutralizing antibodies in the primary and secondary antibody response of cattle to infectious bovine rhinotracheitis virus vaccine.
Calves responded to a single intramuscular injection of an attenuated strain of infectious bovine rhinotracheitis virus by producing IgM followed by IgG antibody. Both IgM and IgG antibody produced during the first month were primarily complement-requiring neutralizing antibody (CRNAb), especially IgM antibody. After a month, IgG had replaced IgM as the predominant immunoglobulin, and titers with and without complement (C') decreased in both IgG and IgM fractions. The largest decrease was in the IgM CRNAb fraction. Seven days after a second injection given on day 196, calves responded with an anamnestic IgG response in which CRNAb titers were 1 or 2 two-fold dilutions higher than non-CRNAb titers. One calf developed an IgM response similar to its primary response, whereas inhibition of the IgM response occurred in the other 3 calves which had much lower IgM antibody titers than those attained in the primary response. Twenty-eight days after the second injection the titers of IgG were the same or only a 2-fold dilution less than their 7-day secondary titers, whereas IgM titers generally decreased considerably more than this. Guinea pig and rabbit sera were equally effective as C' sources in potentiating CRNAb, whereas bovine serum was a poor C' source.
Animals↗
Bovine viral diarrhea virus-specific neutralizing antibodies induced by anti-idiotypic antibodies.
Two murine neutralizing monoclonal antibodies (MAbs), 4D8 and 6D11, recognizing epitopes on gp53, a surface glycoprotein of bovine viral diarrhea virus (BVDV), were used to generate anti-idiotypic antibodies (anti-ids) in a calf. The polyclonal anti-ids were isolated from serum by affinity chromatography on their respective Ab-1-Sepharose columns, followed by repeated adsorption on isotype-matched antibody-Sepharose columns. The anti-ids reacted specifically with their respective Ab-1, but not with isotype-matched controls. They also inhibited the binding of their Ab-1 to BVDV in a concentration-dependent manner. Mice immunized with the two anti-id preparations developed antibodies to BVDV, which neutralized the virus in vitro.
Animals↗
A rapid fluorescent focus-inhibition test for determining dengue neutralizing antibody and for identifying prototype dengue viruses.
Neutralizing antibody to dengue virus in human and animal sera was assayed by the rapid fluorescent focus-inhibition test (RFFIT). Neutralizing-antibody titers could be detected after only 24 h compared to 5--6 days required by the plaque-reduction test. The RFFIT is more definitive than the conventional complement fixation (CF) or hemagglutination-inhibition (HI) test in identifying prototype dengue viruses, is reproducible, and is applicable to the routine detection of neutralizing antibodies to dengue viruses.
Antibodies, Viral↗
Immune responses of humans to a human diploid cell strain of rabies virus vaccine: lymphocyte transformation, production of virus-neutralizing antibody, and induction of interferon.
Lymphocyte transformation, production of neutralizing antibody, and interferon activity of 20 healthy volunteers in response to a human diploid cell strain (HDCS) of rabies virus vaccine were studied. Ten vaccines received 1.0 ml of HDCS vaccine on days 0, 3, 7, and 14, and five of these volunteers received, in addition, 20 international units of human rabies immune globulin/kg of body weight on day 0. All 10 volunteers developed high titers of neutralizing antibody, and eight of the 10 had lymphocytes that were immunologically stimulated by HDCS rabies virus antigen. The interferon responses of eight vaccines to 1.0 ml of HDCS vaccine given intramuscularly on days 0 and 28 and of two vaccines to 1.0 ml of vaccine given intradermally in eight body sites on the same days were measured; low levels of interferon-like activity were found in eight of nine volunteers after the first vaccination, and no activity was found upon revaccination. The high titers of neutralizing antibody that developed did not correlate with lymphocyte stimulation or interferon-like activity, but it is true that all 20 volunteers did develop high titers of neutralizing antibody after 1.0 ml of HDCS vaccine was given intradermally.
Antibodies, Viral↗
Non-human primate LIBRA-Seq accelerates neutralizing antibody discovery in RM vaccinated against HIV-1.
Broadly neutralizing antibodies (bNAbs) exhibit protective efficacy against HIV-1 infection making them an ideal archetype for HIV-1 vaccine design. Presently, no vaccine candidate has induced antibody responses capable of meaningful protection against the swathe of circulating, difficult to neutralize tier 2 HIV-1 viruses. However, the development of stabilized, native-like envelope (Env) trimers such as BG505.SOSIP.664.T332N (BG505 SOSIP) has marked a significant advancement in vaccine design, due to their ability to elicit NAbs that neutralize tier 2 viruses in rhesus macaques (RM). NAb development following envelope trimer immunization in RM remains poorly understood, with hypothesized contributions from genetic variation at the IG loci, naive B cell repertoire, and differential gene expression in B cell lineages. To address these knowledge gaps, we have developed a set of BG505 SOSIP probes capable of recovering paired clonotype identity, antigen specificity, and gene expression of B cells in a high throughput fashion. These probes were constructed by conjugating biotinylated BG505 SOSIP to streptavidin covalently linked to both sc-RNA-Seq compatible DNA oligonucleotides and flow cytometry compatible fluorophores. Using these reagents, we isolated and sequenced BG505 SOSIP specific memory B cells from the PBMCs of an RM that developed high titers of neutralizing antibodies. To benchmark the accuracy of our technology, we compared our recovered heavy and light chain sequences to those identified from the same animal using conventional methodology and recovered 100% of previously identified NAbs. We then applied this technology to recover BG505 SOSIP specific memory B cells from five additional vaccinated RMs, cloned 34 antibodies for functional characterization, and identified ten antibodies with autologous neutralizing activity.
Animals↗
Type specificity of complement-requiring and immunoglobulin M neutralizing antibody in initial herpes simplex virus infections of humans.
Studies comparing the enhancing effect of guinea pig complement on homotypic and heterotypic neutralizing antibodies produced in initial herpes simplex virus (HSV) infections of humans indicated that antibodies to HSV type 1 and HSV type 2 were enhanced to about the same extent, and there was no signigicant difference in the degree to which complement enhanced homotypic and heterotypic HSV-neutralizing antibody. Homotypic and heterotypic immunoglobulin G neutralizing antibodies were enhanced by complement to as great, or greater, an extent as immunoglobulin M (IgM) HSV antibodies in the same sera. In patients with initial HSV type 1 infections, the IgM neutralizing antibody response was type specific. On the other hand, patients with initial HSV type 2 infections produced both homotypic and heterotypic IgM neutralizing antibody. An initial HSV type 2 infection in an individual previously infected with HSV type 1 elicited the production of IgM neutralizing antibody to both HSV type 1 and HSV type 2. However, patients with recurrent HSV type 1 infections failed to produce IgM antibody to either HSV type during reactivation of the virus.
Antibodies, Viral↗
Immune perturbations in HIV-1-infected individuals who make broadly neutralizing antibodies.
Induction of broadly neutralizing antibodies (bnAbs) is a goal of HIV-1 vaccine development. bnAbs occur in some HIV-1-infected individuals and frequently have characteristics of autoantibodies. We have studied cohorts of HIV-1-infected individuals who made bnAbs and compared them with those who did not do so, and determined immune traits associated with the ability to produce bnAbs. HIV-1-infected individuals with bnAbs had a higher frequency of blood autoantibodies, a lower frequency of regulatory CD4+ T cells, a higher frequency of circulating memory T follicular helper CD4+ cells, and a higher T regulatory cell level of programmed cell death-1 expression compared with HIV-1-infected individuals without bnAbs. Thus, induction of HIV-1 bnAbs may require vaccination regimens that transiently mimic immunologic perturbations in HIV-1-infected individuals.
Journal Article↗
Long-term follow-up studies on herpes simplex antibodies in the course of cervical cancer: patterns of neutralizing antibodies.
The kinetics of neutralization was used to study antibodies to herpes simplex virus type 2 in 90 patients with invasive carcinoma of the cervix uteri. The first sera were drawn before treatment and consective sera were drawn at intervals thereafter. Control groups consisted of 90 age-matched healthy women and 70 cancer patients suffering from malignancies other than cervix carcinoma. Patients surviving during the observation period of 12-60 months had a significantly higher frequency of neutralizing antibodies than control groups. Twenty-six of the women with cervix carcinoma died during the observation period and 13 others had a recurrence of the cancer. Survivors with advanced cervical cancer had higher antibody titers than survivors with less severe cervical cancer while patients whose cancer caused death had low titer or to a great extent lacked neutralizing antibodies. Women with recurrences and progressing cervical lesions had no detectable antibodies while women with recurrences and regressing lesions all had antibodies. There was a rise in K2-values 6-18 months after treatment. In serum samples collected later than 18 months, there was a return to original levels.
Adult↗
Development of HIV-1 group-specific neutralizing antibodies after seroconversion.
OBJECTIVE: To study the induction of group-specific (gs) neutralizing antibodies to HIV-1 after seroconversion. DESIGN AND METHODS: Serum samples taken sequentially from seven Dutch homosexual men and four British haemophiliacs (anonymous sample, therefore sex not known) before and after seroconversion were tested for neutralizing antibodies effective against five diverse HIV-1 strains. Strains of HIV-1 tested included isolates from the United States, Europe and Africa. RESULTS: The gs neutralizing antibody response varied between individuals. Only five of the 11 individuals studied produced detectable neutralizing antibodies to laboratory-adapted HIV-1 strains (for example, IIIB) within 32 weeks of seroconversion. Most individuals initially produced antibodies effective against US/European isolates; the response then generally broadened to include the more diverse strains, i.e., African. CONCLUSIONS: These results suggest that the gs neutralizing target for HIV-1 is poorly immunogenic in vivo and is probably not highly conserved among diverse HIV-1 strains.
HIV Antibodies↗
Host immune responses after administration of inactivated Venezuelan equine encephalomyelitis virus vaccines. II. Kinetics of neutralizing antibody responses in donors and adoptively immunized recipients.
Lymphoid cell responses to immunization with various formalin-inactivated Venezuelan equine encephalomyelitis (VEE) virus vaccines were monitored in mice by assessment of the development of both the neutralizing antibody response in sera of spleen cell donors and the adoptive neutralizing antibody response induced by spleen cell transfer in recipients. Donors immunized intraperitoneally with formalin-inactivated VEE vaccine (a single dose or a dose on three consecutive days) developed early serum neutralizing antibody responses (larger than or equal to 1:88-1:100) by seven days after immunization. Recipients of spleen cells from such mice were, however, incapable of eliciting a neutralizing antibody response (less than or equal to 1:10). Only spleen cells from donors immunized with inactivated VEE vaccine plus adjuvants (particularly complete Freund's adjuvant and Bordetella pertussis) were consistently capable of producing early, high-titer serum neutralizing antibody responses in adoptively immunized recipients (larger than or equal to 1:50-1:120 on day 4). The magnitude of neutralizing antibody responses of donors to inactivated VEE vaccines did not serve as a useful indicator of whether spleen cells from such mice could adoptively induce antibody responses in recipients. Finally, treatment of immune spleen cells with rabbit antiserum to mouse thymocytes, but not with rabbit antiserum to mouse gamma-globulin or normal rabbit serum, abolished the capacity of such cells to transfer an antibody response adoptively.
Adjuvants, Immunologic↗
Neutralizing antibodies to canine distemper and measles virus in multiple sclerosis.
Serum neutralizing antibody to canine distemper virus (CDV) was measured in 142 patients with multiple sclerosis (MS), an equal number of age and sex-matched normal controls, and 75 patients with other neurological disorders. An elevated antibody titer was found in the MS population compared to controls. Measles-neutralizing antibody was also found to be elevated in 128 patients with MS. The mean ratio of measles to CDV antibody was similar in the control and MS groups, but a wide range of measles to CDV ratios was found in individual patients and controls. No significant correlation was found between IgG levels and neutralizing antibody titers in MS sera. While the increased titer of measles and CDV antibody may represent a non-specific immunological response, these findings are also consistent with the hypothesis that CDV or a closely related measles virus may stimulate the increased level of measles and CDV antibodies found in MS sera.
Adolescent↗
Evidence that active protection following oral immunization of mice with live rotavirus is not dependent on neutralizing antibody.
Studies were performed to determine whether active immunity against murine rotavirus (EDIM) infection of mice correlated with titers of neutralizing antibody to the challenge virus. Neonatal mice administered either murine or heterologous rotaviruses all developed diarrhea and high titers of serum rotavirus IgG. However, only mice given EDIM, the murine EB, or simian SA11-FEM strains were protected against EDIM infection when challenged 60 days later. Other serotype 3 strains (RRV, SA11-SEM), as well as strains belonging to serotypes 5 and 6 (OSU, NCDV, WC3), were not protective. Serum neutralizing antibody titers to EDIM were almost undetectable after rotavirus infection with any strain and could not, therefore, be correlated with protection. Likewise, intestinal neutralizing antibody titers were extremely low 21 days after EDIM infection, and by 60 days after inoculation, EDIM-infected mice had no greater intestinal neutralizing antibody titers than uninoculated controls. Mice inoculated with SA11-FEM as neonates had much higher serum rotavirus IgG responses than mice inoculated as adults, and only those infected with this virus as neonates were protected. Thus, although immunity to EDIM did not correlate with the presence of neutralizing antibody to EDIM, it did correlate with the overall magnitude of the immune response after inoculation with SA11-FEM.
Animals↗
Determination of neutralizing antibodies and specific immunoglobulin isotype levels in infants after vaccination against diphtheria.
Serum samples were obtained from 44 infants vaccinated against diphtheria at the ages of 3, 5 and 12 months with an aluminium-adsorbed diphtheria-tetanus toxoid vaccine containing 15 Lf units of diphtheria toxoid. Toxin-neutralizing antibodies (antitoxin) were measured by the Vero cell assay and IgG, IgM and IgA antibodies against diphtheria toxoid by enzyme-linked immunosorbent assay. A neutralizing antibody titer of 10 corresponded to 0.01 IU/ml, the level considered necessary for short-term protection. Geometric mean neutralizing antibody titers at 3, 5, 6, 12, 13 and 30 months were 28, 21, 173, 61, 1076 and 61. All children had titers of greater than or equal to 10 (greater than or equal to 0.01 IU/ml) between 6 and 30 months of age. At 30 months only 48% had titers of greater than or equal to 100 (greater than or equal to 0.01 IU/ml), the level considered necessary for long-term protection. Geometric mean IgG antibody levels were 13, 36, 216, 64, 649 and 57. IgG antibodies significantly correlated with neutralizing titers and predicted neutralizing antibodies above or below 10 and 100 with an accuracy of 96 and 82%, respectively. IgG antibodies could not, however, be used to predict individual neutralizing antibody titers with great accuracy. IgM antibodies were only detected after the third vaccination. IgA antibodies were not detected in any serum sample from ten infants tested. In conclusion, the Swedish vaccination schedule results in protective antibody levels in infants until at least 30 months of age. The decline of the antibody titers indicates a need for further studies to establish the duration of protection.
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