scholarly journals THE MECHANISM OF TOLERANCE PRODUCED IN RATS TO SHEEP ERYTHROCYTES

1965 ◽  
Vol 121 (5) ◽  
pp. 671-681 ◽  
Author(s):  
Donald A. Rowley ◽  
Frank W. Fitch

Previous studies suggested that an active immune response was partially responsible for maintaining immunological unresponsiveness to sheep erythrocytes. Measurement of the plaque-forming (antibody-releasing) cell response proved to be a sensitive indicator of an immune response to sheep erythrocytes in the absence of detectable circulating antibody to the antigen. The present studies were undertaken to determine whether an active immune process, measured by the plaque-forming cell response, was partially responsible for induction and maintenance of tolerance. Rats injected intraperitoneally with large doses of sheep erythrocytes beginning at the day of birth develop tolerance to the antigen. In this paper, the plaque-forming cell and antibody response to sheep erythrocytes was characterized for rats receiving a single antigen injection at various ages and for rats which received repeated antigen injections as adults. The dose of antigen was the same as that used to produce tolerance; the injection schedule for repeated immunizations was also the same as that used to produce tolerance. Rats receiving a single antigen injection on the day of birth or at age 7 days had no measurable response to the antigen. Rats receiving a single antigen injection at age 17 days and sacrificed 4 days later had an unequivocal response to the antigen. The spleens had about one-tenth as many plaque-forming cells as spleens of adult animals immunized similarly, but the antibody titers were as high as titers for adult animals. Presumably the high titers of these young animals resulted from the high ratio of plaque-forming cells to body weight and blood volume. Adult animals receiving a single antigen injection had a peak or near peak plaque-forming cell response 4 days after immunization; at this time, sera contained high titers of 19S antibody and the numbers of plaque-forming cells in spleens correlated reasonably well with circulating antibody titers. 7S antibody appeared in serum 5 or 6 days after immunization. The numbers of plaque-forming cells declined progressively 2 and 3 weeks after immunization. Repeated twice weekly, injections of the antigen in adult rats produced a marked decline and then stabilization of numbers of plaque-forming cells in spleens. Although the numbers of plaque-forming cells were fewer, titers of 19S and 7S antibody stabilized at high levels. A progressive recovery of the plaque-forming cell response and a rise in antibody titer occurred when the interval between the last 2 injections was increased from 3 to 10, 17, or 32 days. These findings suggested that repeated closely spaced antigen injections interfered with either cell division or maturation of antibody-forming cells. As the interval between injections was increased, additional antibody-forming cells matured or were formed through cell division. Thus, relatively constant antigenic stimulation provided a mechanism for controlling or limiting the response of antibody-forming cells. In the following paper, it will be shown that this mechanism operating together with a homeostatic mechanism which prevents induction of new antibody-forming cells serves to regulate the immune response to repeated injections of antigen.


1965 ◽  
Vol 121 (5) ◽  
pp. 683-695 ◽  
Author(s):  
Donald A. Rowley ◽  
Frank W. Fitch

An active immune response to sheep erythrocytes was demonstrated in rats made "tolerant" to sheep erythrocytes by twice-weekly antigen injections beginning on the day of birth. Groups of tolerant rats were sacrificed 4 days after they had received 5 to 42 antigen injections; spleens were sampled for plaque-forming (antibody-releasing) cells and sera were titrated for antibody to sheep erythrocytes using a sensitive "plate hemolysin" technique. During the 3rd week of life and after the 5th antigen injection, the tolerant rats had an immune response equivalent to that of rats of similar age which had received a single antigen injection, but spleens contained only about one-tenth as many plaque-forming cells as adults animals receiving similar antigen injections. Continued antigen injections produced a marked decline and stabilization of this relatively small population of antibody-forming cells; however, the number of plaque-forming cells in the tolerant rats remained considerably elevated above the numbers of plaque-forming cells present in the spleens of non-immunized animals. The sera from all but 1 tolerant rat had demonstrable antibody to sheep erythrocytes in low titer. A progressive recovery of the plaque-forming cell response and rise in antibody titers occurred in adult tolerant rats when the interval between the last 2 antigen injections was increased from 3 days to 14 or 28 days. The decline and stabilization of numbers of plaque-forming cells occurring with continued injections after the 3rd week of life paralleled a similar decline and stabilization in rats receiving similar antigen injections as adults. Also, the recovery of the plaque-forming cell and antibody response of tolerant animals paralleled the recovery observed when the interval between injections was increased in rats receiving similar antigen injections as adults. These findings suggested that the same mechanism controlled numbers of antibody-forming cells in tolerant and normally responsive adult animals. Repeated closely spaced antigen injections presumably interfered with either cell division or maturation of antibody-forming cells. As the interval between injections was increased, additional antibody-forming cells matured or were formed through cell division. Relatively constant antigenic stimulation provided a mechanism for controlling or limiting the response of antibody-forming cells. The mechanism controlling or limiting the response of antibody-forming cells would not account for the stabilization of numbers of antibody-forming cells at high levels for normal animals and at low levels for the tolerant animals. Passive immunization of growing rats with homologous anti-sheep erythrocyte serum markedly inhibited the plaque-forming cell response of growing rats. It was proposed that antibody produced by the small population of antibody-forming cells in the tolerant rats provided a feedback or homeostatic mechanism which inhibited transformation of potential antibody-forming cells to antibody-forming cells. Thus, tolerance to sheep erythrocytes was induced and maintained by two mechanisms. One mechanism, dependent on relatively constant antigenic stimulation, limited or controlled the numbers of antibody-forming cells. The other, dependent on the production of small quantities of antibody by a few antibody-forming cells, limited or controlled the transformation of potential antibody-forming cells to antibody-forming cells.



2019 ◽  
Vol 26 (7) ◽  
pp. 542-549 ◽  
Author(s):  
Shan Shan Hao ◽  
Man Man Zong ◽  
Ze Zhang ◽  
Jia Xi Cai ◽  
Yang Zheng ◽  
...  

Background: Bursa of Fabricius is the acknowledged central humoral immune organ. The bursal-derived peptides play the important roles on the immature B cell development and antibody production. Objective: Here we explored the functions of the new isolated bursal hexapeptide and pentapeptide on the humoral, cellular immune response and antigen presentation to Avian Influenza Virus (AIV) vaccine in mice immunization. Methods: The bursa extract samples were purified following RP HPLC method, and were analyzed with MS/MS to identify the amino acid sequences. Mice were twice subcutaneously injected with AIV inactivated vaccine plus with two new isolated bursal peptides at three dosages, respectively. On two weeks after the second immunization, sera samples were collected from the immunized mice to measure AIV-specific IgG antibody levels and HI antibody titers. Also, on 7th day after the second immunization, lymphocytes were isolated from the immunized mice to detect T cell subtype and lymphocyte viabilities, and the expressions of co-stimulatory molecule on dendritic cells in the immunized mice. Results: Two new bursal hexapeptide and pentapeptide with amino acid sequences KGNRVY and MPPTH were isolated, respectively. Our investigation proved the strong regulatory roles of bursal hexapeptide on AIV-specific IgG levels and HI antibody titers, and lymphocyte viabilities, and the significant increased T cells subpopulation and expressions of MHCII molecule on dendritic cells in the immunized mice. Moreover, our findings verified the significantly enhanced AIV-specific IgG antibody and HI titers, and the strong increased T cell subpopulation and expressions of CD40 molecule on dendritic cells in the mice immunized with AIV vaccine and bursal pentapeptide. Conclusion: We isolated and identified two new hexapeptide and pentapeptide from bursa, and proved that these two bursal peptides effectively induced the AIV-specific antibody, T cell and antigen presentation immune responses, which provided an experimental basis for the further clinical application of the bursal derived active peptide on the vaccine improvement.



Author(s):  
Elena V Esaulenko ◽  
Aleksey A Yakovlev ◽  
Genady A Volkov ◽  
Anastasia A Sukhoruk ◽  
Kirill G Surkov ◽  
...  

Abstract Background This study compares the immunogenicity and safety of a 3-antigen (S/pre-S1/pre-S2) hepatitis B (HepB) vaccine (3AV), to a single antigen vaccine (1AV) in adults to support the registration of 3AV in Russia. Methods We conducted a randomized, double-blind, comparative study of 3-dose regimens of 3AV (10 μg) and 1AV (20 µg) in adults aged 18–45 years. We evaluated immunogenicity based on hepatitis B surface (HBs) antibody titers at days 1, 28, 90, 180, and 210, adverse and serious adverse events (SAEs) to study day 210. The primary outcome was based on the difference in rates of seroconversion at day 210 (lower bound 95% confidence interval [CI]: > − 4%). Secondary outcomes were seroprotection rates (SPR), defined as anti-HBs ≥10 mIU/mL and anti-HBs geometric mean concentration (GMC). Results Rate of seroconversion in 3AV (100%) was noninferior to 1AV (97.9%) at study day 210 (difference: 2.1%, 95% CI: −2.0, 6.3%]) but significantly higher at study day 28. SPR at study day 210 was >97% in both arms. Anti-HBs titers were significantly higher at study days 90 (P = .001) and 180 (P = .0001) with 3AV. Sex, age, and body mass index (BMI) had no impact on anti-HBs titers. The rates of local reactions related to vaccination were similar between vaccine arms (3AV vs 1AV) after the first (30% vs 18.8%, P = .15), second (20.0% vs 14.6%, P = .33), and third vaccination (14.9% vs 23.4%, P = .22). No SAEs were reported. Conclusions 3AV was noninferior to 1AV. 3AV induced high SPR, and there were no safety concerns. Clinical Trials Registration. NCT04209400.



Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 606
Author(s):  
Giuseppe Cappellano ◽  
Hugo Abreu ◽  
Chiara Casale ◽  
Umberto Dianzani ◽  
Annalisa Chiocchetti

The first vaccines ever made were based on live-attenuated or inactivated pathogens, either whole cells or fragments. Although these vaccines required the co-administration of antigens with adjuvants to induce a strong humoral response, they could only elicit a poor CD8+ T-cell response. In contrast, next-generation nano/microparticle-based vaccines offer several advantages over traditional ones because they can induce a more potent CD8+ T-cell response and, at the same time, are ideal carriers for proteins, adjuvants, and nucleic acids. The fact that these nanocarriers can be loaded with molecules able to modulate the immune response by inducing different effector functions and regulatory activities makes them ideal tools for inverse vaccination, whose goal is to shut down the immune response in autoimmune diseases. Poly (lactic-co-glycolic acid) (PLGA) and liposomes are biocompatible materials approved by the Food and Drug Administration (FDA) for clinical use and are, therefore, suitable for nanoparticle-based vaccines. Recently, another candidate platform for innovative vaccines based on extracellular vesicles (EVs) has been shown to efficiently co-deliver antigens and adjuvants. This review will discuss the potential use of PLGA-NPs, liposomes, and EVs as carriers of peptides, adjuvants, mRNA, and DNA for the development of next-generation vaccines against endemic and emerging viruses in light of the recent COVID-19 pandemic.



1975 ◽  
Vol 141 (1) ◽  
pp. 72-81 ◽  
Author(s):  
D E McFarlin ◽  
S C Hsu ◽  
S B Slemenda ◽  
F C Chou ◽  
R F Kibler

After challenge with guiena pig basic protein (GPBP) Lewis (Le) rats, which are homozygous for the immune response experimental allergic encephalomyelitis (Ir-EAE) gene, developed positive delayed skin tests against GPBP and the 43 residue encephalitogenic fragment (EF); in addition, Le rat lymph node cells (LNC) were stimulated and produced migration inhibitory factor (MIF) when incubated in vitro with these antigens. In contrast Brown Norway (BN) rats, which lack the Ir-EAE gene, did not develop delayed skin tests to EF and their LNC were not stimulated and did not produce MIF when incubated in vitro with EF. These observations indicate that the Ir-EAE gene controls a T-cell response against the EF. Le rats produced measurable anti-BP antibody by radioimmunoassay after primary challenge. Although no antibody was detectable in BN rats by radioimmunoassay, radioimmunoelectrophoresis indicated that a small amount of antibody was formed after primary immunization. After boosting intraperitoneally, both strains of rat exhibited a rise in anti-BP antibody; which was greater in Le rats. In both strains of rat the anti-BP antibody reacted with a portion of the molecule other than the EF. Since EF primarily evokes a T cell response, it is suggested that the EF portion of the BP molecule may contain a helper determinant in antibody production.





2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A880-A880
Author(s):  
Abigail Overacre-Delgoffe ◽  
Hannah Bumgarner ◽  
Anthony Cillo ◽  
Ansen Burr ◽  
Justin Tometich ◽  
...  

BackgroundColorectal cancer (CRC) is one of the most common and deadly cancers in the US, and the survival rate for advanced cases is poor. While immunotherapy has revolutionized cancer treatment, CRC remains largely unresponsive, with only ~6% of patients responding to anti-PD1. Specific microbiome signatures are associated with anti-PD1 response in melanoma patients; however, the underlying mechanism remains unclear. While the microbiome in cancer patients has been extensively studied, the endogenous immune response to these microbes and the subsequent effects on cancer immunity remain unstudied. Most microbes reside within the gut, and bacteria that adhere to the intestinal epithelium can stimulate bacteria-specific immune responses. Therefore, we hypothesized that the microbiome, especially adherent, immunogenic bacteria, may support anti-tumor immunity through activation of local microbiota-specific T cells.MethodsUsing a carcinogen-induced mouse model of CRC, we sought to determine the impact of microbiome modulation on the anti-tumor immune response. We colonized tumor-bearing mice with Helicobacter hepaticus (Hhep) and assessed tumor burden, survival, and immune infiltration. Lymphocytes were isolated from the tumor and surrounding tissue when tumors were terminal (12 weeks). We utilized TCR transgenic mice and MHC class II tetramers to track the spatial and transcriptional Hhep-specific T cell response through 5’ single cell RNAseq, flow cytometry, and spectral immunofluorescence.ResultsHhep colonization in tumor-bearing mice led to decreased tumor burden and significantly improved survival. Interestingly, colonization induced activation of Hhep-specific T follicular helper cells (TFHs) that supported formation of mature peri- or intra-tumoral tertiary lymphoid structures (TLS). The presence of TLS led to increased infiltration of cytotoxic lymphocytes (T and NK cells) within the tumor core. Surprisingly, the anti-tumor response was dependent on CD4+ T and B cells but not CD8+ T cells. Using TFH KO mice, we found that Hhep-specific CD4+ T cells were both necessary and sufficient to drive TLS maturation and anti-tumor immunity.ConclusionsHere, we demonstrate that addition of a single bacterial species after tumor formation leads to a reduction in CRC tumor burden and increased survival through TLS maturation. This microbiome-dependent remodeling of the tumor microenvironment is driven by Hhep-specific TFH cells that are both necessary and sufficient for tumor control, demonstrating for the first time that microbiota-specific T cells contribute to anti-tumor immunity. Overall, these findings suggest that microbiome modulation and the subsequent microbiota-specific CD4+ T cell response may represent a new variety of immunotherapies for cancers that remain resistant to checkpoint blockade.



Vaccines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 964
Author(s):  
Kelsey A. Pilewski ◽  
Kevin J. Kramer ◽  
Ivelin S. Georgiev

Vaccination remains one of the most successful medical interventions in history, significantly decreasing morbidity and mortality associated with, or even eradicating, numerous infectious diseases. Although traditional immunization strategies have recently proven insufficient in the face of many highly mutable and emerging pathogens, modern strategies aim to rationally engineer a single antigen or cocktail of antigens to generate a focused, protective immune response. However, the effect of cocktail vaccination (simultaneous immunization with multiple immunogens) on the antibody response to each individual antigen within the combination, remains largely unstudied. To investigate whether immunization with a cocktail of diverse antigens would result in decreased antibody titer against each unique antigen in the cocktail compared to immunization with each antigen alone, we immunized mice with surface proteins from uropathogenic Escherichia coli, Mycobacterium tuberculosis, and Neisseria meningitides, and monitored the development of antigen-specific IgG antibody responses. We found that antigen-specific endpoint antibody titers were comparable across immunization groups by study conclusion (day 70). Further, we discovered that although cocktail-immunized mice initially elicited more robust antibody responses, the rate of titer development decreases significantly over time compared to single antigen-immunized mice. Investigating the basic properties that govern the development of antigen-specific antibody responses will help inform the design of future combination immunization regimens.



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