Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Immunologic Memory”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources
PubMed2005

The effect of aging on cognate function and development of immune memory.

Immunological memory is one of the central features of the immune system and can be described as the ability of the immune system to respond more efficiently to a second encounter with the same pathogen. The immune system is dramatically affected by age-related changes and it is becoming apparent that immune memory exhibits significant defects as a result of aging. Although immune memory generated during youth functions well into old age, that generated later in life functions poorly. Importantly, age-related defects in the cognate helper function of CD4(+) T cells can potentially influence the development of both humoral and cell-mediated immune memory. These defects ultimately result in aged individuals who exhibit reduced responses to both infections and vaccinations.

Aging↗
PubMed1988

Secondary antibody responses to thymus-independent antigens. Decline and life-span of memory.

Immunological memory has been defined by the finding that upon a secondary injection of an antigen into an animal the immune response obtained differs from the response produced after the first inoculation of the antigen, independent of the length of time that can elapse between the first and second contact with antigen. In this report we have investigated the life-span of memory to a thymus-independent antigen, trinitrophenylated lipopolysaccharide (TNP-LPS), using a cell transfer system that allows the study of the function of isolated LPS-reactive "memory" B cells from C57BL/6 mice in histocompatible LPS-nonresponder C57BL/10ScCr hosts. We found that the longer the elapse of time between the transfer of TNP-LPS-primed C57BL/6 cells and the challenge of hosts with TNP-LPS, the lower the anti-TNP serum antibody level of the secondary response, i.e. in the absence of antigen, TNP-LPS memory cells have a short life-expectancy in the adoptive hosts as they do not persist for more than one or two weeks after transfer. Our present results suggest that induction and long-term persistence of memory to TNP-LPS in adoptive hosts cannot be solely explained by the long life-span of a subpopulation of antigen-specific memory B cells, but rather through the continuous recruitment of newly formed cells and probably antigen persistence.

Animals↗
PubMed1966

Quantitative studies of the adoptive immunological memory in mice. I. An age-dependent barrier to syngeneic transplantation.

Antibody-forming cells suspended from a mouse spleen and transferred to intact animals of the same genotype face a barrier which severely affects their capacity to implant and/or to function. This phenomenon was quantitatively studied in a model system which, utilizing the immunogenic properties of human serum albumin in mice, allows the secondary response of the transferred cells to be followed without interference from the host's own reactivity. The barrier to syngeneic transplantation was found (a) to be radiosensitive (500 R X-rays to the recipient abolishes it and insures optimal functional conditions to the donor cells) in the same order of magnitude of other mammalian systems involving rapidly dividing cell populations, and (b) to depend upon the age of the recipient: its linear rise is documented from birth time (when approximately 50% of the maximal immune capacity of the transfer is expressed) to the age of 2 months ( approximately 1 %). The significance of these findings to the immune response and to cell growth and differentiation is discussed.

Animals↗
PubMed1990

The effects of stress on the development of immunological memory following low-dose antigen priming in mice.

Observable stress effects on immune responses may be a function of the quantitative and qualitative characteristics of the stressor, and the outcome measurement of immunity. Further, the effects of stress on humoral immunity, in particular, may be sensitive to the concentrations of antigen used to elicit a response. We have studied the effects of footshock stress during the time of priming with low concentrations of antigen on the secondary response to another low dose of antigen. The secondary humoral immune response of C3H/HeJ mice to the protein antigen keyhole limpet hemocyanin was examined following footshock, exposure to the apparatus without shock, or exposure to the home cage. Footshock reproducibly depressed the IgG anti-KLH response, and the effect on the IgM response was sporadic. Initially, footshock was administered for 7 days before and 7 days after priming with low amounts of antigen. Subsequent studies demonstrated that a single footshock session delivered 24 h after priming could suppress the IgG anti-KLH response.

Animals↗
PubMed1968

Relationship of germinal centers in lymphoid tissue to immunological memory. I. Evidence for the formation of small lymphocytes upon transfer of primed splenic white pulp to syngeneic mice.

The fate, proliferation, and developmental potentialities of cell suspensions made from white pulp containing large germinal centers have been studied in the mouse by transfer of cells labeled with thymidine-(3)H to lethally irradiated, syngeneic recipients. Radioautographic analyses were made using both smears and sections of a variety of tissues. Thymidine-(3)H-labeling patterns of white pulp showed that, initially, labeling occurred in a majority of blast and "intermediate cells" but in very few or no small lymphocytes. After intravenous transfer, most of the labeled cells localized in the lymphoid tissues of spleen, lymph nodes, and Peyer's patches. Few cells migrated to the thymus, lung, liver, and intestinal mucosa. Both after intravenous and after intraperitoneal transfer there was a rapid increase in the incidence of labeled small lymphocytes and a decrease of labeled blasts and intermediate cells. This was accompanied by an increase in the grain count of the small lymphocytes and a progressive decrease in the grain counts of the blast cells. Exposure of nonlabeled donor cells to thymidine-(3)H at various time intervals after transfer indicated that dividing cells were present early after transfer but that their incidence progressively decreased. Between 24 and 48 hr, very little cell division was detectable.

Animals↗
PubMed1968

Relationship of germinal centers in lymphoid tissue to immunological memory. II. The detection of primed cells and their proliferation upon cell transfer to lethally irradiated syngeneic mice.

White-pulp cells and whole spleen from donor mice immunized with sheep erythrocytes were transferred intravenously to heavily irradiated mice. The numbers of plaque-forming cells and the amount of hemagglutinating antibody produced after reexposure to antigen were measured. When reexposure to sheep erythrocytes was delayed, a much greater response occurred in the transferred cells. Peak responsiveness was reached at 24 hr after transfer. This "lag effect" was greatly reduced by repeated injections of 5-bromodeoxyuridine into the recipient mice prior to challenge with antigen. It was therefore concluded that much of the increase in responsiveness was due to a proliferation of "primed" cells after cell transfer. The fact that a significant response was given by the transferred cells in spite of 5-bromodeoxyuridine treatment suggested that some of the primed cells were nondividing. White pulp was a much richer source of responsive cells than was whole spleen.

Animals↗
PubMed1969

The proliferative and anamnestic antibody response of rabbit lymphoid cells in vitro. I. Immunological memory in the lymph nodes draining and contralateral to the site of a primary antigen injection.

Popliteal lymph nodes were obtained from rabbits 4 days to 9 months after a primary injection of diphtheria toxoid or bovine gamma-globulin into the footpad. The ability of cells from these nodes to proliferate upon reexposure to antigen in vitro was compared to the height of the secondary response produced by tissue fragments. In addition, a comparison was made between the responsiveness of draining and contralateral lymph nodes. While the secondary antibody response in vitro increased markedly with the time after immunization at which the lymph nodes were taken from the animals, the degree of proliferation induced by antigen was highest with cells from lymph nodes taken early after priming (peak day 7) and was very much lower with lymph node cells taken longer than 3 wk after priming. This striking difference between these two responses has been discussed. Contralateral lymph nodes were much inferior to draining nodes in their ability to give a secondary antibody response in vitro, and never gave a detectable proliferative response. This difference became less marked with time after priming, but could still be demonstrated after 4 months. These results suggest a concentration of primed cells in the lymphoid tissue draining the site of injection, and a slow release of these cells into the circulation, to be distributed to the remaining lymphoid tissue.

Animals↗
PubMed1970

Immunological memory in mice. I. Physical separation and partial characterization of memory cells for different immunoglobulin classes from each other and from antibody-producing cells.

Plaque forming cells (PFC) of different immunoglobulin classes producing antibodies against sheep erythrocytes were separated according to their buoyant densities by means of equilibrium centrifugation in a stepwise BSA gradient. In the period of 7-10 days after immunization gammaM PFC are markedly enriched in fractions of low density and relatively depleted in fractions of high density. The distribution of total gammaG PFC shows less enrichment in the lower density fractions and less depletion in the higher density fractions. The density profile for gammaG(2a) PFC is even flatter, with a significant difference (depletion) relative to the unseparated spleen cells only in the highest density fraction. The density gradient distributions of cells able to transfer an adoptive immune response of the various immunoglobulin classes are markedly different from the PFC distribution. Cells obtained 7-10 days after immunization able to transfer an IgM response are present in the same proportions across the density gradient, whereas memory cells for gammaG(2a) obtained at this time are markedly enriched in fractions of low density and virtually depleted from high density fractions. With increasing time after primary immunization, the gammaG(2a) memory cells increase progressively in density and by 6 weeks the higher and lower density fractions have the same proportions of gammaG(2a) memory cells. The total gammaG (mainly gammaG(1)) memory cells by 7-10 days show slight enrichment in low density fractions and no depletion in high density fractions. The conclusions were reached that (a) memory for gammaG(1) develops earlier than memory for gammaG(2a) and (b) that memory for anti-SRBC antibodies of different classes is carried in separate cells. When gradient fractions enriched for PFC and memory cells for all classes were completely depleted of PFC using glass bead columns, the ability of this fraction to transfer memory for all classes was not diminished. This shows that memory cells are not identical with cells secreting antibodies.

Animals↗
PubMed1970

Immunological memory in mice. II. Cell interactions in the secondary immune response studies by means of immunoglobulin allotype markers.

Congenic mice, differing genetically only at the loci coding for immunoglobulin H chain (or Fc) structures, have been used to study cell interactions in the 7S (gammaG(2a)) antibody response to sheep erythrocytes (SRBC), as detected by the Jerne plaque-forming cell (PFC) method. The interaction between thymus and bone marrow cells was studied in adult thymectomized irradiated recipients, protected with syngeneic bone marrow and injected with thymus cells from the partner congenic strain. All of the gammaG(2a) PFC detected in the spleens of these mice were of bone marrow allotype. Adoptive secondary immune responses were then studied to determine whether a similar interaction between memory cells and bone marrow derived cells could be detected. Primed spleen cells from the partner congenic strain, or a subpopulation of these cells obtained by BSA density gradient fractionation, were injected into irradiated recipients alone, or together with syngeneic nonimmune spleen or bone marrow cells. All gammaG(2a) PFC detected in these experiments were of primed cell allotype. There was no evidence that antibody forming cell precursors in normal spleen or bone marrow participate in the adoptive secondary immune response detected 7 days after transfer of primed spleen cells. This was true regardless of whether the bone marrow cells were injected at the time of transfer, or were injected 1-2 wk earlier and allowed to become established in the spleens of recipient mice. Although no specific cell interaction was seen, bone marrow (and, to a lesser degree, normal spleen) cells were found to have a nonspecific enhancing effect on the adoptive secondary response when they were injected together with the primed spleen cells. This enhancement was not evident if the bone marrow cells were injected 1 or 2 wk prior to primed cell transfer.

Animals↗