Development Of Humoral Immune Response Research Articles

Host‐Dependent Serum Specificity to the V3 Domain of HIV‐1

The previous studies of anti-HIV-1 humoral immune response have found the stable individual structural bias in the antibody production that reflects the changes in the immune functional network caused by HIV-1. The correlation between antigen structure, in particular the V3 domain of HIV-1, and the serum specificity to the structure remains unclear. To clarify the role of host individual factors in the serum specificity, we used the slightly modified HIV-1 serotyping methodological approach for the sera of the patients infected with HIV-1 with a different level of genetic similarity. Substantial discrepancy between serum specificities and antigen structure was found. Patients infected with HIV-1 carrying similar and identical V3 sequences had significantly different serum specificities. The opposite situation was often observed as well. The results of the study suggest that the influence of the V3 loop structure in the development of humoral immune response to the V3 loop is substantially modified in a patient-specific manner.

Expression of CD137 (4-1BB) on human follicular dendritic cells.

Follicular dendritic cells (FDCs) are the antigen (Ag)-trapping accessory cells of the germinal centres (GCs), essential for the development of humoral immune responses and memory. FDCs reside in the microenvironment of secondary lymphoid tissue where Ag-activated B cells expand, and undergo isotype switching and affinity maturation prior to becoming memory B cells. In addition to delivering Ag, FDCs also provide potent nonspecific accessory signals to the B cells, which are important for the GC reaction. In this report, we show that human tonsilar FDCs express the costimulatory molecule CD137. Surface expression of CD137 on FDCs was confirmed by immunofluorescent labelling and fluorescence-activated cell sorter analysis. CD137 was also highly expressed by the human cell line HK, which displays many characteristics of in vivo FDCs. The interaction between B cells and FDCs is essential for the GC reactions, and our finding suggests that CD137 plays a role in FDC-regulated B-cell responses.

Composition and biological activity of submerged mycelium of the xylotrophic basidiomycete Lentinus edodes

The composition of submerged mycelium of Lentinus edodes, grown in laboratory fermenters, has been studied. The mycelium contained 23-24% proteins, 8-9% lipids, up to 1800 mg% phenolic substances, and a significant amount of inorganic substances, including calcium and iron. The fungus produced up to 5.0% intracellular and 3.5-4.0 g/l extracellular polysaccharides. The submerged mycelium stimulated the development of humoral immune response elicited by sheep red blood cells.

Linognathus vituli (Anoplura: Linognathidae): population growth, dispersal and development of humoral immune responses in naı̈ve calves following induced infestations

Growth of Linognathus vituli populations following establishment at a point source was followed for 16 weeks on eight louse-naı̈ve Holstein calves. Dispersal of lice from the point of infestation (withers) was monitored by examination of known louse predilection sights. Mean louse indices increased during the initial weeks reaching maximum mean values at 8 weeks post-infestation (p.i.). Subsequently, mean indices decreased, reaching a plateau that persisted through weeks 14 and 15 p.i. There was little movement away from the withers until 5 weeks p.i. Subsequently, numbers of lice on the withers declined, while increasing at sites on the head. A few lice were noted on the dewlap and topline sites. Host antibody responses to crude nymph antigens, measured by enzyme-linked immunosorbent assay (ELISA), were generally evident within 2–4 weeks of infestation. Examination of individual host data showed louse populations could be categorized relative to the mean population size for the group. Two animals were considered ‘chronic’, having louse populations that persisted throughout the study and whose louse indices were >150% of the group mean. Two animals were classified as ‘resistant’ having lice present for only a portion of the study and whose louse indices <40% of the group mean. The remaining animals had louse indices between 62 and 137% of the group mean. Antibody profiles of the individuals were not as clearly categorized, although the ‘resistant’ animals were only positive for short periods of time, roughly corresponding to the time when lice were observed.

Regulated expression of human histocompatibility leukocyte antigen (HLA)-DO during antigen-dependent and antigen-independent phases of B cell development.

Human histocompatibility leukocyte antigen (HLA)-DO, a lysosomal resident major histocompatibility complex class II molecule expressed in B cells, has previously been shown to be a negative regulator of HLA-DM peptide loading function. We analyze the expression of DO in human peripheral blood, lymph node, tonsil, and bone marrow to determine if DO expression is modulated in the physiological setting. B cells, but not monocytes or monocyte-derived dendritic cells, are observed to express this protein. Preclearing experiments demonstrate that ∼50% of HLA-DM is bound to DO in peripheral blood B cells. HLA-DM and HLA-DR expression is demonstrated early in B cell development, beginning at the pro-B stage in adult human bone marrow. In contrast, DO expression is initiated only after B cell development is complete. In all situations, there is a striking correlation between intracellular DO expression and cell surface class II–associated invariant chain peptide expression, which suggests that DO substantially inhibits DM function in primary human B cells. We report that the expression of DO is markedly downmodulated in human germinal center B cells. Modulation of DO expression may provide a mechanism to regulate peptide loading activity and antigen presentation by B cells during the development of humoral immune responses.

Hypothalamo-pituitary system controls the development of humoral immune response during prenatal ontogenesis in rats

We studied the influence of the neuroendocrine system on the development of humoral immune response to sheep erythrocytes in rat fetuses. The removal of brain in utero by decapitation of 18-day fetuses induced a fourfold increase in the number of antibody-forming cells in the liver, as compared to the unoperated fetuses. After the removal of the forebrain, including hypothalamus (encephalectomy), the number of antibody-forming cells was comparable to that in unoperated fetuses. The observed increase in the number of antibody-forming cells in the liver was not due to a disturbed migration of precursors of B-lymphocytes in the spleen, since their content in the spleen was also four times that in the encephalectomized and unoperated fetuses. The increased number of antibody-forming cells in decapitated fetuses could be due to an enhanced proliferative activity of the lymphocytes in the liver of these fetuses. It has been proposed that humoral immunity is controlled by the hypothalamo-pituitary-adrenal system already during prenatal development; the adrenocorticotropic hormone and glucocorticoids appear to be involved in this regulation.

Modulation of orientation and exploratory behavior in mice during development of humoral immune response.

We demonstrated opposite changes in the orientation and exploratory behavior of (CBAxC57Bl/6)F(1) mice in the open field test during the formation of primary humoral immune response. These changes depended on initial behavioral activity: the exploratory behavior was suppressed in animals with initially high activity, stimulated in animals with medium reaction, and remained unchanged in mice with initially low activity. The detected changes in the exploratory behavior during the formation of immune response were leveled in the total population (not divided by initial behavioral status).

A malariometric survey in a rural community in the Muheza District, Tanzania: age profiles in the development of humoral immune responses

A malariometric survey was carried out in a rural community situated in a malaria holoendemic endemic area of Tanzania. A random sample ( n=228) of different age groups was taken to elucidate the association between anti-Pf155/RESA and anti-Pf332 antibody responses and classical malaria indices. Parasitaemia, fever, splenomegaly, haematocrit and antimalarial consumption were assessed. Antibody responses against Pf155/RESA and Pf332 peptides were determined by ELISA. The age profiles of parasite density, splenomegaly, fever, haematocrit values and prevalence of antibody responses indicated intensive malaria exposure and the highest impact of malaria in small children. Forty-five percent of the study population had detectable chloroquine and desethyl-chloroquine blood levels, and the highest frequency and concentrations were recorded in the 12–23 months old. There was no significant association between the presence of drug and parasite density in the different age groups, although in the <15 years old there was lower parasite prevalence among the children positive for drug in their blood ( P<0.05). High prevalence of antibody responses to all antigens was observed already at an early age, but the mean anti-Pf155/RESA and anti-Pf332 antibody levels increased significantly only in the adult group ( P<0.01). Significantly lower mean parasite densities were observed in high responders to Pf155/RESA and Pf332 peptides for the ≥10 years old. For the 1–9 years, a similar difference was only observed in the high responders to Pf332. For the whole material, anti-Pf155/RESA and anti-Pf332 antibody levels correlated positively with age. When the effect of age was allowed for in analysing the relationship between parasite density and antibody level against the different antigens, a significant negative correlation was found only with regard to Pf332 in the ≥10 years age group. These results suggest that anti-Pf332 antibodies appear to be a better indicator for antiparasitic immunity, but both antigens are important for immune protection.

Clinical and laboratory alterations in horses during immunization with snake venoms for the production of polyvalent (Crotalinae) antivenom

Six horses were immunized with the venoms of Bothrops asper, Crotalus durissus durissus and Lachesis muta stenophrys for the production of polyvalent (Crotalinae) antivenom. During the immunization, clinical and laboratory alterations were evaluated in these animals, and the development of humoral immune response was followed. Only moderate local tissue changes (edema, abscesses, fistules and fibrosis) were observed in these animals, whereas no systemic alterations occurred. Regarding laboratory tests, there was a drop in hemoglobin concentration and hematocrit, together with an increment in total serum protein. Horses developed a moderate leukocytosis, with increments in polymorphonuclear leukocytes and lymphocytes. No significant changes were observed in prothrombin time or platelet count. There were no alterations in serum lactic dehydrogenase and gamma glutamyl transferase activities, whereas minor increments in creatine kinase and alanine aminotransferase activities were observed, together with a decrease in aspartate aminotransferase. All these changes occurred after the injection of 9 mg venom, when sodium alginate was first used as adjuvant. Creatinine levels had a small increment, although no changes were observed in urea levels or in the urea creatinine ratio. An important individual variability was observed in the humoral immune response, as judged not only by enzyme-linked immunosorbent assay, but also by assessing the neutralization of the indirect hemolytic activity of venoms.

Different CD40-mediated signaling events require distinct CD40 structural features.

Signals delivered to B cells through CD40 are critical to the development of humoral immune responses. In this study we characterize regions of the 62-amino acid cytoplasmic domain of human CD40 (hCD40) that are essential for signal transduction and examine the functional consequences of mutations in these regions. A panel of mutant hCD40 molecules was stably expressed in mouse B cell lines and tested for its ability to stimulate Ab secretion, homotypic adhesion, and increased surface expression of B7, Fas, CD23, LFA-1, and intracellular adhesion molecule-1. Our results indicate that CD40 contains at least two major signaling determinants in the cytoplasmic domain: one disrupted by a truncation of 22 amino acids, and a second disrupted by the removal of 10 additional amino acids. The second determinant includes threonine 234, a residue previously shown to be important in CD40 signal transduction. Our functional analysis of alanine and serine substitutions at position 234 indicates that phosphorylation of this residue may be important for full CD40 signaling activity.

Immunization with T cell receptor V beta chain peptides deletes pathogenic T cells and prevents the induction of collagen-induced arthritis in mice.

Collagen-induced arthritis (CIA) in susceptible strains of mice is an animal model of T cell-mediated inflammatory polyarthritis. Analysis of T cell receptor (TCR) V beta gene usage in cells isolated from arthritic joints of BUB/BnJ (BUB) mice (H-2q, TCR V beta a) showed that TCR V beta chain gene usage was limited to TCR V beta 3 and V beta 10 gene families. All of the BUB mice immunized with a mixture of TCR V beta 3 and TCR V beta 10 peptides, but not with control TCR V beta 14 peptide, were refractory to the induction of CIA. Immunization with TCR V beta 3 and V beta 10 peptides completely blocked the development of clinical and subclinical inflammation, formation of pannus and synovial hyperplasia, and the erosion of cartilage and bone. Further studies revealed that preimmunization of BUB mice with V beta 10 peptide alone was sufficient to render the mice resistant to CIA. Analysis of TCR V beta chain gene expression in lymph node cells from arthritic and arthritis-protected mice showed the expression of TCR V beta 10 subfamily in all of the arthritic mice, but not in arthritis-protected mice. Immunization with TCR V beta peptides did not diminish the humoral responses to chicken type-II collagen and also elicited significant levels of anti-V beta 3 and anti-V beta 10 peptide antibodies. Antibodies cross-reactive with mouse chicken type-II collagen were detected in both the arthritic and arthritis-protected mice. Adoptive transfer of serum from arthritis-protected BUB mice significantly delayed the onset (P < 0.005) of arthritis in recipient BUB mice. In contrast, mice injected with serum from arthritic mice had early onset of arthritis. These results demonstrate that immunization of BUB mice with TCR V beta chain peptides elicited antibodies reactive with the self-TCR and prevented the induction of collagen-induced arthritis by eliminating or downregulating pathogenic T cells and consequently blocking the development of humoral immune response. These findings may have clinical applications in treating human autoimmune diseases characterized by common TCR gene usage.

Clearance pathways of soluble immune complexes in the pig. Insights into the adaptive nature of antigen clearance in humans.

Efficient delivery of immune complexes (ICs) to the mononuclear phagocytic system, and subsequent IC processing, may prevent their potentially harmful effects in other tissues and may also be important in the development of humoral immune responses. In mice, rabbits, and primates, the liver and spleen are the main sites of IC clearance. It has been demonstrated previously that the pulmonary capillaries in the pig are lined with macrophages and that certain particulates, including bacteria, localize to this organ. In this study, we used gamma scintigraphy to explore the sites and kinetics of clearance of soluble IC comprising 123I-labeled hepatitis B surface Ag (HBsAg):porcine anti-HBsAg in the Large White pig. At t = 10 min after i.v. injection, 43 +/- 5% (mean +/- SE) IC localized in the lungs, and 36 +/- 6% counts in the liver. At t = 85 min, values were: lungs, 15 +/- 4% and liver, 29 +/- 2%. Findings were similar following intraarterial injection. Complement depletion resulted in more rapid initial IC clearance (t1/2 = 5 min), reduced lung uptake (23 +/- 3% at 10 min), and impaired IC catabolism. In normal animals, 5 to 7% injected IC bound to PBMCs, but no E binding was seen. A fall in PBMC numbers (46 to 59% of baseline), was observed following IC injection. These findings contrast with our previous observations using analogous IC in humans, in which we did not observe any change in peripheral blood leukocyte counts consequent upon complex processing, suggesting that in humans, Es may function as a buffering system for complement-bearing IC in the circulation, preventing their interaction with leukocytes bearing complement and FcR, and the potential activation of these cells.

Age-dependent humoral responses of children to mycobacterial antigens

In the United States, disseminated infection with environmental mycobacteria, including the Mycobacterium avium complex, is the most common opportunistic bacterial infection seen in AIDS patients. However, the source and relative degree of exposure to environmental mycobacteria during childhood are unknown. To examine the age-related exposure to mycobacteria, we obtained serum samples from 150 children ranging in age from 6 months to 18 years. Each sample was tested against both M. avium (serovar 1) sonic extracts and mycobacterial lipoarabinomannan, using an enzyme-linked immunosorbent assay (ELISA). All serum samples were also subjected to immunoblot analysis with the sonic extract antigen. These studies established that elevated ELISA values (P < 0.0001) and increased immunoblot reactivity (P < 0.0001) against mycobacterial antigens were both associated with increasing age. The seroreactivity differences were most striking when comparing the age groups of children below the age of 6 with the older age groups. Our results suggest that the development of humoral immune responses to mycobacterial antigens in children correlates with increasing age and that there may be an environmental factor predisposing to mycobacterial exposure which is related to advancing age.

A prospective study of humoral immune responses to cow milk antigens in the first year of life.

Previous studies have shown that in cow milk allergy the specific immune response to dietary cow milk antigens is deficient. This study aimed at delineating the development of humoral immune response to cow milk antigens in healthy infants. Twenty-five healthy newborns were enrolled, and seen at scheduled visits at the ages of three, six and eleven months, and they formed two groups: those breastfed and those fed adapted cow milk formulae. The local immune response in the gut was approximated using the ELISPOT assay of circulating antibody secreting cells. At the age of three months, in the formula fed group, cells secreting specific IgA to cow milk antigens were detected despite low levels of IgA serum antibodies. The total number of IgA secreting cells increased with age (p = 0.001). The milk in the infant diet directly influenced this development so that the age related increase was significantly greater in the formula fed group (p = 0.04). The results indicate that diet has a significant effect on the developing immune system, and that healthy infants are able to respond in an antigen specific fashion to dietary antigens, which may be central in attaining clinical tolerance of such antigens.

Effect of danazol on estrogen-and progesterone-receptor systems of the human endometrium

Blast cells obtained from the "erythropoietic spleen" of FG-stimulated young mice and cells accumulating in the spleens of preleukemic AKR mice have a marked suppressive effect on spontaneous and mitogen-induced proliferation of young mouse splenocytes in vitro and suppress the development of humoral immune response in immunized recipients during syngeneic transfer in vivo. Some disturbances in erythron system in preleukemic AKR mice manifested in the accumulation of immature erythroid precursors which are suppressors of immunocompetent lymphocytes are suggested to be a pathogenetic link in the development of leukemia.

Contact sensitivity to dinitrofluorobenzene and oxazolone in mice: In vitro cell-electrophoretic assay

Prevalent techniques for the assessment of cell-mediated immunity (CMI) in vitro are time consuming and may lack specificity. Deriving from the earlier observation of reduction in mean electrophoretic mobility (EPM) of lymphocytes following the development of humoral immune response, the possibility of using this electrokinetic method for the assessment of contact sensitivity in vitro was tested. CBA mice epicutaneously sensitized to dinitrofluorobenzene and 2-phenyl 4-ethoxy oxazolone showed a marked and reproducible reduction in the mean EPM of their lymph node cells (LNC). The specificity of this alteration in surface charge density was established by the enhancement in the EPM of contact sensitized LNC upon subsequent incubation in vitro with the specific antigen only. The profiles of time kinetics of changes in the EPM of LNC before and after incubation with antigen were virtually parallel to those of in vivo delayed hypersensitivity (DH) reaction as measured by the ear-swelling method. The coefficients of correlation between the reduction in EPM and in vivo DH response for DNFB and oxazolone were 0.89 and 0.86 respectively. EPM measurements may thus provide a sensitive, rapid, and quantitative parameter for the assessment of CMI in vitro.

Effect of partial hepatectomy on induction of cells inhibiting development of the humoral immune response

It has been shown that partial hepatectomy inhibits the induction of cells exerting a suppressant effect on the development of humoral immune response.

Hepatitis B vaccine: efficacy in high-risk settings, a two-year study.

A formalin-treated hepatitis B vaccine in the form of purified hepatitis B surface antigen (HBsAg) was prepared from asymptomatic human HBsAg carriers. Its safety and potency were tested in 5 chimpanzees. The vaccine was administered to 264-individuals. The results of the first 173 immunizations--46 hemodialysis patients and 127 staff members--are presented. Potency was ascertained and efficacy assessed by the development of humoral immune responses to HBsAg (anti-HBs antibody) and seroepidemiologic studies of vaccinated and nonvaccinated subjects. The results, 2 years after immunization, suggest that the vaccine was protective against hepatitis B infection in high-risk hemodialysis settings. Preliminary studies with an inactivated hepatitis B vaccine similarly prepared, but with aluminum hydroxide as adjuvant, indicate that a such a preparation induces a more rapid and stronger anti-HBs response.

MATURATION OF THE HUMORAL IMMUNE RESPONSE IN MICE

In spite of the prenatal appearance of immunoglobulin-bearing lymphocytes and theta-positive lymphocytes in the spleens of Swiss-L mice, these mice are not able to produce detectable levels of humoral antibodies in response to antigen until after 1 wk of age. Adult levels of response are not achieved until 4-8 wk of age. In the presence of bacterial lipopolysaccharides, which can substitute for or enhance T-cell function, the B cells from young Swiss-L mice were found to be indistinguishable in function from adult B cells, both with respect to the numbers of plaque-forming cells (PFC) produced in vitro in response to antigen and with respect to the kinetics of PFC induction. The spleen cells from young Swiss-L mice are significantly less sensitive than adult spleen cells, however, to stimulation by the T cell mitogens, concanavalin A (Con A) and phytohemagglutinin (PHA). Very few Con A-responsive cells could be detected at birth but the numbers increased sharply with age until 3 wk after birth. On the other hand, PHA-responsive cells could not be detected in the spleen until about 3 wk of age. The latter cells were found to respond also to Con A, but at a lower dose (1 microg/ml) than that required for the bulk of the Con A-responsive cells (3 microg/ml). The cells that respond both to PHA and to Con A appear in the spleen at about the time that Swiss-L mice acquire the ability to produce humoral antibodies, and these cells can be depleted from the spleen by the in vivo administration of antithymocyte serum. The development of humoral immune responses in these mice therefore appears to be correlated with the appearance of recirculating T lymphocytes that are responsive both to PHA and to Con A.