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Lifespan of human lymphocyte subsets defined by CD45 isoforms.

The lifespan of thymic-derived or T lymphocytes is of particular interest because of their central role in immunological memory. Is the recall of a vaccination or early infection, which may be demonstrated clinically up to 50 years after antigen exposure, retained by a long-lived cell, or by its progeny? Using the observation that T lymphocyte expression of isoforms of CD45 corresponds with their ability to respond to recall antigens, we have investigated the lifespan of both CD45R0 (the subset containing responders, or 'memory' cells) and CD45RA (the unresponsive, or 'naive' subset) lymphocytes in a group of patients after radiotherapy. Here we report rapid loss of unstable chromosomes from the CD45R0 but not the CD45RA pool. Immunological memory therefore apparently resides in a population with a more rapid rate of division. Differing survival curves for the two subsets are best described by a model in which there is also reversion in vivo from the CD45R0 to the CD45RA phenotype. Expression of CD45R0 in T cells may therefore be reversible.

Chromosome Aberrations↗

Studies on delayed hypersensitivity to protein antigen. Induction of delayed hypersensitivity by chemically modified antigen.

it was shown in our previous paper that mice primed with chemically modified bacterial alpha-amylase (BaA), which was neither cross-reactive with anti-BaA antibody nor able to induce a humoral anti-BaA response, developed enhanced responses to a subsequent challenge with native BaA and that the magnitude of the immunological memory was closely related to the priming dose of modified BaA. This paper describes the experimental conditions for induction of delayed hypersensitivity (DH) by modified BaA in relation to the development of immunological memory for antibody response to native BaA. Mice primed with either an intraperitoneal (i.p.) or subcutaneous (s.c.) injection of modified BaA in complete Freunds adjuvant (CFA) developed enhanced anti-BaA as the immunogen and modified BaA as the eliciting antigen, the relationship of anti-BaA responses to a subsequent challenge with BaA. In contrast, when mice were immunized with an s.c. injection of the modified BaA only, a significant level of DH to native BaA could be induced, as measured by the footpad reaction (FPR). The highest degree of DH was observed in mice given 50 micrograms of modified BaA. DH was detectable within 5 days and persisted for 25 days after immunization. In the reciprocal combination of native BaA as the immunogen and modified BaA as the eliciting antigen, the relationship of anti-BaA responses to DH was examined. The primary anti-BaA responses induced by an i.p. injection of large doses of BaA was markedly higher than those induced by an s.c. injection, while DH was exhibited only in mice given s.c. injection of BaA in CFA. With respect to DH to native BaA induced by the modified BaA, it was shown that C3H/He mice were high and C57BL/6 mice were low responders.

Amylases↗

Social stress in male mice impairs long-term antiviral immunity selectively in wounded subjects.

An important property of the antiviral immune response is its time-dependent character. Beginning with a few antigen-specific cells upon infection, it evolves to a stage where there is an abundance of antigen-specific cells and antibodies that are needed to clear the pathogen, and ends with circulating antibodies and a population of virus-specific memory cells to protect the animal from reinfection. Short-term effects of stress on the immune system have been investigated extensively, showing that stress acutely changes many aspects of immunity. However, relatively little is known about the consequences of stress for the quality and quantity of long-term immunological memory. In the present study, we have investigated the effect of social stress, applied in mice at Days 1, 2 and 3 after inoculation with a herpes virus, on long-term antibody and memory cytokine responses to the virus. Male mice were subjected to three 5-min confrontations with an aggressive conspecific. Approximately half of the mice was wounded by bites of the aggressor during this stress procedure, and these mice were analyzed separately from nonwounded mice. It appeared that wounded mice showed suppressed protective antibody responses and impaired memory for virus-specific IL-4 and IL-10 production, whereas mice that were not wounded showed intact long-term immune responses and memory. It is concluded that the combination of wounds and the social stress of repeated confrontations is associated with impaired protective immunity as a consequence of suppressed antibody levels and impairment of some aspects of antiviral immunological memory.

Aggression↗

Homeostasis-stimulated proliferation drives naive T cells to differentiate directly into memory T cells.

The developmental requirements for immunological memory, a central feature of adaptive immune responses, is largely obscure. We show that as naive CD8 T cells undergo homeostasis-driven proliferation in lymphopenic mice in the absence of overt antigenic stimulation, they progressively acquire phenotypic and functional characteristics of antigen-induced memory CD8 T cells. Thus, the homeostasis-induced memory CD8 T cells express typical memory cell markers, lyse target cells directly in vitro and in vivo, respond to lower doses of antigen than naive cells, and secrete interferon gamma faster upon restimulation. Like antigen-induced memory T cell differentiation, the homeostasis-driven process requires T cell proliferation and, initially, the presence of appropriate restricting major histocompatibility complexes, but it differs by occurring without effector cell formation and without requiring interleukin 2 or costimulation via CD28. These findings define repetitive cell division plus T cell receptor ligation as the basic requirements for naive to memory T cell differentiation.

Adoptive Transfer↗

[Processing of optic and acoustic sensory impressions in the brain. 1].

1. Methods for identifying central disturbances of hearing. Histology and physiology of the optic and acoustic conducting paths. 2. Sensory physiology and technology of information. The special position of speech and understanding of speech in physiology and technic. 3. Excitation of nerves as an electrical and chemical event. 4. Transformation of stimuli. 5. Different types of memory. Optic and acoustic memory. Learning and forgetting. 6. The genetical memory. 7. The immunological memory. 8. The neuronal memory. The concentrated collection of optical and acoustical information in the cells. 9. Awareness of sensory impressions. The limitation of physico-chemical explanations. 10. Body structure and soul. The body-spirit problem from the philosophical view point.

Adolescent↗

Evaluation of De-O-acetylated meningococcal C polysaccharide-tetanus toxoid conjugate vaccine in infancy: reactogenicity, immunogenicity, immunologic priming, and bactericidal activity against O-acetylated and De-O-acetylated serogroup C strains.

The polysaccharide capsule of serogroup C Neisseria meningitidis (MenC) has been integral to vaccine development. Licensed MenC vaccines contain the O-acetylated (OAc+) form of polysaccharide. Some MenC strains have de-O-acetylated (OAc-) polysaccharide, which may affect antibody specificity and functional activity when used in a vaccine. We evaluated an OAc-MenC conjugate-tetanus toxoid conjugate (MCC-TT) vaccine given concomitantly with whole-cell diphtheria-tetanus-pertussis, Haemophilus influenzae type b, and oral polio immunization in 83 infants at 2, 3, and 4 months of age. Serum bactericidal activities (SBA) against OAc+ and OAc- MenC strains and OAc+ and OAc- polysaccharide-specific immunoglobulin G (IgG) levels were evaluated. MCC-TT vaccine was well tolerated. All infants produced SBA titers of > or = 8 after a single dose at 2 months of age. The SBA geometric mean titer for OAc+ strain C11 increased from 2.7 (95% confidence interval [CI] 2.2 to 3.2) to 320 (95% CI, 237 to 432), 773 (95% CI, 609 to 982), and 1,063 (95% CI, 856 to 1319) after one, two, and three doses of MCC-TT, respectively. OAc- IgG levels were twice as high as OAc+ IgG levels after the primary series of MCC-TT vaccine, and the SBA was significantly higher against the OAc- MenC strain. Antibody responses to booster vaccination with either OAc+ MenC polysaccharide vaccine (MACP) or a fourth dose of MCC-TT at 14 months of age provided evidence of immunologic memory. The acetylation status of the booster vaccine influenced the specificity of the response, with significantly higher OAc- IgG levels and SBA after MCC-TT vaccine compared to MACP vaccine but similar OAc+ antibody levels. MCC-TT vaccine is highly immunogenic and primes for immunologic memory against OAc+ and OAc- MenC strains in infancy.

Antibodies, Bacterial↗

Studies on B-cell memory. I. Generation and exhaustion of B-cell memory by thymus-dependent antigen in T-cell depleted mice.

Mice depleted of T cells by adult thymectomy, X-irradiation and reconstitution with syngeneic bone marrow cells, either untreated or treated with anti-Thy-1 serum and complement, were immunized intensively with alum-precipitated bovine serum albumin (AP-BSA) along with or without bacterial lipopolysaccharide (LPS), but no significant anti-BSA antibody response was detected. Priming of the T-cell depleted mice, however, either by a single injection of AP-BSA plus LPS or by multiple injections of AP-BSA without LPS, resulted in the generation of immunological memory. A single injection of AP-BSA without LPS was ineffective. The memory required the aid of syngeneic T cells to be recalled by the challenge with AP-BSA plus LPS. On the other hand, multiple injections of AP-BSA plus LPS did not cause the generation of memory and the response of these mice to the challenge was lower than that of unprimed control mice. These results suggest that (1) the anti-BSA response is highly dependent on the helper function of T cells, (2) the degree of T-cell requirement for the memory generation is very low, and (3) priming with too much strong stimulation in the absence of functional T cells leads to the suppression or abortion of previously generated immunological memory.

Animals↗

Do self-perpetuating B lymphocytes drive human autoimmune disease?

Normal immunological memory is thought to be underpinned by T lymphocytes. However, in rheumatoid arthritis there are indications that T-lymphocyte control has been subverted by self-perpetuating B lymphocytes. Potential mechanisms in other autoimmune states are less clear, but a number of observations suggest that misappropriation of immunological memory by B lymphocytes may be a common feature of human autoantibody-associated disease. Put simply, autoantibodies drive their own production. If so, the availability of safe B-lymphocyte-depleting agents provides a potential means for reversal of autoimmunity.

Arthritis, Rheumatoid↗

Abnormalities of measles antibody response in human immunodeficiency virus type 1 (HIV-1) infection.

The finding that severe measles occurs in immunized as well as nonimmunized human immunodeficiency virus (HIV)-infected individuals suggests that both immunologic memory and the initial response to measles may be impaired by HIV infection. That the initial response is affected was supported by the finding that post-measles immunization titers of HIV-infected babies were significantly lower (p = 0.01) than those of normal babies. Poor immunologic memory was evidenced in HIV-infected children by lower titers than in normal children (p < 0.001) and by a continuing decline in measles antibody that was not arrested by reimmunization. Impaired memory appeared to be associated with defective avidity maturation. HIV-infected babies and infants or children had a significantly lower avidity index (AI) than age-matched normal children (p < 0.01). HIV-infected adults, who were infected with HIV following infection with measles, did not have AI values significantly different from normal adults (p = 0.18) but had significantly greater values than did HIV-infected babies and children (p < 0.01). Thus, in contrast to infants and children who were infected with HIV before measles immunization, the adult immune response to measles was less affected.

Adult↗

[Immune responsiveness of high and low antibody producing lines of mice against an antigen non-cross-reacting with the selection antigen (author's transl)].

Mice genetically selected for high (HL) or low (LL) antibody responsiveness to sheep erythrocytes (SE) also differed in the immune response to other antigens. We have studied in details the non-specific effect of the selection on responsiveness to bovine seralbumin (BSA) that is an antigen non cross-reacting with SE. BSA has been used either heat-aggregated (H-BSA) or alum-precipitated (Al-BSA). The characteristics of the response to H-BSA and to SE both injected intravenously were similar in several aspects: ranges of interline difference in agglutinin response were equivalent; minimal immunogenic doses were lower in HL than in LL mice. As for SE, the use of an adjuvant (Al-BSA) increased the response of LL more than that of HL mice, so the interline difference decreased. The interline difference between minimal immunogenic doses was weaker with Al-BSA than with H-BSA (100 times and 10,000 times respectively). The threshold dose for induction of immunologic memory was lower in the HL than in LL mice. For Al-BSA this threshold dose was higher than the minimal immunogenice dose in both lines; for H-BSA it was higher (in HL) or equal (in LL) to the minimal immunogenic dose. The results of this article confirm that the selective breeding for SE responsiveness has modified the antibody response to BSA in a similar way. The group of genes controlling the level of antibody response are also responsible for the induction of immunological memory.

Alum Compounds↗

Safety and immunogenicity of meningococcus serogroup C conjugate vaccine administered as a primary or booster vaccination to healthy four-year-old children.

BACKGROUND: Meningococcal C conjugate (Men C) vaccines have been routinely used in the UK since November, 1999. Little information exists regarding antibody persistence or immunologic memory after infant vaccination or response to a first dose at 4 years. METHODS: Ninety-five children immunized at 2, 3 and 4 months of age with 0 or 3 doses of Men C vaccine, boosted with Men C or meningococcal A/C polysaccharide vaccine at 12 months, received a single dose of Men C vaccine at 4 years; 103 age-matched controls were recruited. Pre- and postvaccination Men C IgG (enzyme-linked immunosorbent assay) antibody titers and serum bactericidal activity (SBA) were measured. Safety data were also collected. RESULTS: Baseline SBA titers of > or =1/4 were observed in 87% of children after at least 3 doses of Men C vaccine in infancy compared with 21% of controls. Reciprocals of postvaccination SBA geometric mean titers in those with four prior doses [3803 (95% confidence interval 3489, 4146)] were significantly higher than controls [33 (95% confidence interval 20, 55)] ( < 0.001). Memory was attenuated by the 12-month meningococcal A/C polysaccharide booster [734 (95% confidence interval 484, 1115)] ( < 0.001). All children had IgG responses to a first dose of Men C vaccine, 80% achieving SBA titers of > or =1/4 (77% > or =1/8). The vaccine was safe and well-tolerated. CONCLUSION: Infant immunization with Men C produced persistent antibody and immunologic memory at 4 years. All children made IgG antibodies after a first dose at this age, with 80% showing bactericidal activity. Clarification of the best measures of Men C vaccine-induced protection is needed, through correlation of immunogenicity data such as this with UK vaccine efficacy estimates.

Antibodies, Bacterial↗

Early immunisation with hepatitis B vaccine: a five-year study.

We evaluated the response to the recombinant Hepatitis B vaccine using an accelerated schedule versus the traditional schedule by studying the immunologic memory induced in 200 children with HBs-Ag negative mothers. At seroconversion, the traditional schedule presented a higher percentage of children with serum HBs-Ag concentrations over 100 mIU/ml than the accelerated schedule. After five years this difference was no longer statistically significant and children who presented anti-HBsAg concentrations below 10 mUI/ml received an additional booster dose which stimulated the antibody concentration to exceed 100 mIU/ml in all cases. Recombinant HBV vaccine induced better long term immunologic memory when it was administered earlier.

Antibodies↗

Reduction of tumorigenicity by an interferon-gamma-gene-transduced tumor on another syngeneic tumor in a murine model.

To evaluate the effect of interferon-gamma-gene-transduced cells, DS mice were inoculated into their footpads with syngeneic mammary adenocarcinoma SC42 admixed with interferon-gamma producing mammary adenocarcinoma SC115Kgamma, which had been established by an interferon-gamma-gene transduction in another syngeneic mammary adenocarcinoma SC115 using retroviral vectors. These mice rejected both tumor cells and developed resistance to subsequent challenges with either SC115 or SC42 cells inoculated into their opposite posterior footpads. These results thus indicate that systemic immunological memory to each of the independent tumor cell lines developed in these mice. Although the SC42 cells admixed with irradiated SC115Kgamma cells were rejected by these mice, the SC42 cells admixed with irradiated SC115neoR, in which the neo-gene had been transduced, were observed to proliferate. Tumor rejection was reversed by an in vivo administration of anti-interferon-gamma antibody, thus suggesting that locally produced interferon-gamma plays an important role in tumor elimination and immunological memory induction. In conclusion, interferon-gamma-gene-transduced tumor cells are therefore considered to have a therapeutic potential for other types of malignant tumor cell lines.

Adenocarcinoma↗

[Comparison of the action of carminomycin and rubomycin on the dynamics of the primary and secondary immune responses].

The effect of rubomycin and carminomycin on the dynamics of the primary and secondary immune response and formation of the immunologic memory to sheep red cells in mice was studied. Differences in the character of the antibiotics effect indicative of the higher selective action of carminomycin on multiplying cells, precursors of the antibody-forming plasmids, were found. Theoretically interesting discrepancies in the effect of the antibiotics on the content of the antibodies in the serum and the antibody-producing cells in the spleen were shown. It was demonstrated that carminomycin had no effect on formation of the immunologic memory inspite of a noticeable decrease in the total number of the spleen nuclear cells and the number of the antibody-forming cells at the moment of immunization under the effect of the antibiotic.

Animals↗

Gene therapy for T cell-mediated autoimmunity: teaching the immune system how to restrain its own harmful activities by targeted DNA vaccines.

We recently used a modification of gene therapy (naked DNA vaccination) to induce immunological memory against self-pro-inflammatory chemokines such as macrophage inflammatory protein-1 alpha or monocyte chemoattractant protein-1, and against the pro-inflammatory cytokine tumor necrosis factor-alpha. First, DNA constructs encoding each of the different pro-inflammatory mediators together with a repeated immunostimulatory sequence were prepared. Then, experiment animals were subjected to a repeated administration of each construct. Under these conditions, tolerance to the product of each insert was broken, and immunological memory established. Upon induction of experimental autoimmune encephalomyelitis, a T cell-mediated autoimmune disease of the central nervous system that serves as a model for multiple sclerosis or adjuvant induced arthritis, this memory was "turned on" to provide DNA-vaccinated animals a high state of disease resistance. Antibodies to the product of each inserted gene were isolated form these animals. Each antibody was found capable of neutralizing in vitro the chemoattractive properties of each relevant chemokine, thereby transferring disease resistance. Interestingly, the level of their production was dependent on disease severity, that is, each titer was accelerated in accordance with disease progression. Thus, by using a simple gene therapy technique the immune system could be "re-educated" to restrain its own harmful activities.

Animals↗

[Induction of antitumor immune response in the mouse model after vaccination with B7.1 expressing tumor cells].

The aim of the study was the induction of an antitumor immune response by genetic modification of tumor cells. This was done by transfecting the costimulatory molecule B7.1 into a murine tumor cell line SCCVII/SF in order to increase T cell recognition and to install an immunologic memory. One cohort of immunocompetent mice C3 H/HeN were injected with B7.1 expressing tumor cells, while the control group received parental B7.1 negative tumor cells. In a second step those immunized mice were rechallenged by parental tumor cells and tumor growth was compared to a new control group. Transfection with B7.1 prohibits outgrowth of the SCCVII cell line. Animals that have been vaccinated in this way are partially immune towards a secondary exposition to B7.1 negative tumor cells. Outgrowth of this recurrent tumor is slowed down. Such an immunization builds up an immunologic memory. Vaccination with B7.1 expressing tumor cells lead to a partial protective tumor immunity in the SCCVII-C3 H/HeN mouse model.

Animals↗

Natural and vaccine-induced immunity against Haemophilus influenzae type b in patients with beta-thalassemia.

Natural and vaccine-induced immunity and immunological memory to Haemophilus influenzae type b (Hib) were evaluated in adolescents and adults with beta-thalassemia. At baseline 10/23 (43%) unvaccinated patients had naturally acquired anticapsular antibodies >0.15 microg/ml, the threshold of protection, compared to 9/10 (90%) aged-matched controls. Hib-conjugate vaccine (PRP-T) induced protective immune responses in all subjects and there were no differences in geometric mean concentrations at 1 month (GMC) between patients and controls (69.04 versus 40.5, respectively). Vaccine-induced immunological memory was assessed in 12 subjects with beta-thalassemia who had been vaccinated against Hib in the past. All subjects had retained PRP>1 microg/ml at baseline; PRP-T revaccination induced anamnestic responses which were similar, in terms of post vaccination antibody concentration (P=0.54) and avidity (P=0.08), with primary responses given by previously unvaccinated patients. A single dose of PRP-T induces adequate and long-lasting immunity and should be given in all unvaccinated adolescents and adults with beta-thalassemia.

Adolescent↗

Maintenance of serum antibody levels.

In vertebrates, serum antibodies are an essential component of innate and adaptive immunity and immunological memory. They also can contribute significantly to immunopathology. Their composition is the result of tightly regulated differentiation of B lymphocytes into antibody-secreting plasma blasts and plasma cells. The survival of antibody-secreting cells determines their contribution to the immune response in which they were generated and to long-lasting immunity, as provided by stable serum antibody levels. Short-lived plasma blasts and/or plasma cells secrete antibodies for a reactive immune response. Short-lived plasma blasts can become long-lived plasma cells, probably by competition with preexisting plasma cells for occupation of a limited number of survival niches in the body, in a process not yet fully understood. Limitation of the number of long-lived plasma cells allows the immune system to maintain a stable humoral immunological memory over long periods, to react to new pathogenic challenges, and to adapt the humoral memory in response to these antigens.

Animals↗