Adjuvant-guided type-1 and type-2 immunity: infectious/noninfectious dichotomy defines the class of response.
Traditionally, protein Ags have been injected in CFA (oil with inactivated mycobacteria) to induce immunity and with IFA (oil alone) to induce tolerance. We report here that injection of hen eggwhite lysozyme, a prototypic Ag, in CFA-induced and IFA-induced pools of hen eggwhite lysozyme-specific memory T cells of comparable fine specificity, clonal size, and avidity spectrum, but with type-1 and type-2 cytokine signatures, respectively. This adjuvant-guided induction of virtually unipolar type-1 and type-2 immunity was observed with seven protein Ags and in a total of six mouse strains. Highly polarized type-1 and type-2 immunity are thus readily achievable through the choice of adjuvant, irrespective of the genetic bias of the host and of the nature of the protein Ag. This finding should have far-reaching implications for the development of vaccines against infectious and autoimmune diseases. Furthermore, our demonstration that Ag injected with IFA is as strongly immunogenic for T cells as it is with CFA shows that the presence of the mycobacteria determines not the priming of naive T cells through the second-signal link but the path of downstream differentiation toward CD4 memory cells that express either type-1 or type-2 cytokines. (+info)
Humoral response suppression observed with CD23 transgenics.
CD23, also known as the low affinity IgE receptor (FcepsilonRII), has been hypothesized to have a role in IgE regulation. A new CD23 transgenic mouse was generated using the MHC class I promoter and IgH enhancer to further test the hypothesis that CD23 plays a role in the down-regulation of IgE. Study of three founder lines by FACS showed overexpression to varying extents on both B and T lymphocytes. No alterations in lymphocyte populations was observed. All three founder lines exhibited strong suppression of IgE in response to DNP-keyhole limpet hemocyanin/alum and Nippostrongylus brasiliensis infection compared with that in parental or littermate controls. The founder line exhibiting the highest level of suppression also was less susceptible to Ag-induced systemic anaphylactic shock. Overall, the data support the concept that enhancing CD23 levels can be used to suppress IgE-mediated disease. The mechanism involves decreased IgE synthesis, because the serum half-life of IgE was not altered in transgenics, and enzyme-linked immunospot analysis demonstrated lower IgE-producing cells stimulated by injection of anti-IgD. Transgenics also exhibited significantly decreased IgG1 responses and exhibited lower levels of all Ig isotypes, although this was more variable in different founder lines. (+info)
Effects of aluminum potassium sulfate on learning, memory, and cholinergic system in mice.
AIM: To study the relationship between aluminum potassium sulfate (APS) and memory deficits of mice. METHODS: 30, 60, or 90 d after the mice were given daily APS i.g., the step-through latency (STL) was determined with a passive avoidance task. Aluminum (Al) contents in brain and blood were assayed with atomic absorption spectrophotometry. Acetylcholine (ACh) content in brain was determined with chemiluminescent method and choline acetyltransferase (ChAT) activity was measured radiochemically. RESULTS: APS 1 g.kg-1 increased blood-Al only after 30 d. After 60 d, STL, ACh content and ChAT activity decreased by 46.4%, 8.5%, and 22.6%, respectively. These parameters decreased by 50%, 11.1%, and 27.8%, respectively, with increased Al in blood and brain, after 90 d. APS 0.25 g.kg-1 had no effects on mice except blood-Al. In ethylcholine mustard aziridium chloride (AF64A) treated mice, APS 1 g.kg-1 only increased blood and brain-Al. CONCLUSION: The intake of APS 1 g.kg-1.d-1 for 60 d induced learning and memory deficits in mice. (+info)
Disturbance of cerebral function in people exposed to drinking water contaminated with aluminium sulphate: retrospective study of the Camelford water incident.
OBJECTIVE: To establish whether people exposed to drinking water contaminated with 20 tonnes of aluminium sulphate in the Camelford area of Cornwall in the south west of England in July 1988 had suffered organic brain damage as opposed to psychological trauma only. DESIGN: Retrospective study of affected people. PARTICIPANTS: 55 affected people and 15 siblings nearest in age to one of the group but who had not been exposed to the contaminated water were studied. MAIN OUTCOME MEASURES: Various clinical and psychological tests to determine medical condition and anxiety levels in affected people. Assessment of premorbid IQ (pFSIQ) with the national adult reading test, a computerised battery of psychomotor testing, and measurement of the difference in latencies between the flash and pattern visual evoked potentials in all participants. RESULTS: The mean (SE) pFSIQ was above average at 114.4 (1.1). The most sensitive of the psychomotor tests for organic brain disease was the symbol digit coding (SDC) test (normal score 100, abnormal <85). PARTICIPANTS performed less well on this test (54.5 (6.0)) than expected from their pFSIQ (P<0.0001) and a little less poorly on the averaged less discriminating tests within the battery (86.1 (2.5), P<0.0001). In a comparison with the 15 sibling pairs (affected people's age 41.0 (3.3) years v sibling age of 42.7 (3.1) years (P=0.36) the exposed people had similar pFSIQ (114.7 (2.1)) to their siblings (116.3 (2.1), (P=0.59) but performed badly on the symbol digit coding test (51.8 (16.6)) v (87.5 (4.9) for siblings, P=0.03). The flash-pattern differences in exposed people were greater than in 42 unrelated control subjects of similar age (27.33 (1.64) ms v 18. 57 (1.47) ms, P=0.0002). The 15 unexposed siblings had significantly better flash-pattern differences than their affected siblings (13.4 (2.4) ms v 29.6 (2.9) ms, P=0.0002). No effect of anxiety could be shown on these measurements from the analysis of the anxiety scores of exposed people. CONCLUSION: People who were exposed to the contaminated water at Camelford suffered considerable damage to cerebral function, which was not related to anxiety. Follow up studies would be required to determine the longer term prognosis for affected individuals. (+info)
Protective immunity using recombinant human IL-12 and alum as adjuvants in a primate model of cutaneous leishmaniasis.
Protection from cutaneous leishmaniasis, a chronic ulcerating skin lesion affecting millions, has been achieved historically using live virulent preparations of the parasite. Killed or recombinant Ags that could be safer as vaccines generally require an adjuvant for induction of a strong Th1 response in murine models. Murine rIL-12 as an adjuvant with soluble Leishmania Ag has been shown to protect susceptible mice. We used 48 rhesus macaques to assess the safety, immunogenicity, and efficacy of a vaccine combining heat-killed Leishmania amazonensis with human rIL-12 (rhIL-12) and alum (aluminum hydroxide gel) as adjuvants. The single s.c. vaccination was found to be safe and immunogenic, although a small transient s.c. nodule developed at the site. Groups receiving rhIL-12 had an augmented in vitro Ag-specific IFN-gamma response after vaccination, as well as increased production of IgG. No increase in IL-4 or IL-10 was found in cell culture supernatants from either control or experimental groups. Delayed hypersensitivity reactions were not predictive of protection. Intradermal forehead challenge infection with 107 metacyclic L. amazonensis promastigotes at 4 wk demonstrated protective immunity in all 12 monkeys receiving 2 microgram rhIL-12 with alum and Ag. Partial efficacy was seen with lower doses of rhIL-12 and in groups lacking either adjuvant. Thus, a single dose vaccine with killed Ag using rhIL-12 and alum as adjuvants was safe and fully effective in this primate model of cutaneous leishmaniasis. This study extends the murine data to primates, and provides a basis for further human trials. (+info)
Archaeosome vaccine adjuvants induce strong humoral, cell-mediated, and memory responses: comparison to conventional liposomes and alum.
Ether glycerolipids extracted from various archaeobacteria were formulated into liposomes (archaeosomes) possessing strong adjuvant properties. Mice of varying genetic backgrounds, immunized by different parenteral routes with bovine serum albumin (BSA) entrapped in archaeosomes ( approximately 200-nm vesicles), demonstrated markedly enhanced serum anti-BSA antibody titers. These titers were often comparable to those achieved with Freund's adjuvant and considerably more than those with alum or conventional liposomes (phosphatidylcholine-phosphatidylglycerol-cholesterol, 1. 8:0.2:1.5 molar ratio). Furthermore, antigen-specific immunoglobulin G1 (IgG1), IgG2a, and IgG2b isotype antibodies were all induced. Association of BSA with the lipid vesicles was required for induction of a strong response, and >80% of the protein was internalized within most archaeosome types, suggesting efficient release of antigen in vivo. Encapsulation of ovalbumin and hen egg lysozyme within archaeosomes showed similar immune responses. Antigen-archaeosome immunizations also induced a strong cell-mediated immune response: antigen-dependent proliferation and substantial production of cytokines gamma interferon (Th1) and interleukin-4 (IL-4) (Th2) by spleen cells in vitro. In contrast, conventional liposomes induced little cell-mediated immunity, whereas alum stimulated only an IL-4 response. In contrast to alum and Freund's adjuvant, archaeosomes composed of Thermoplasma acidophilum lipids evoked a dramatic memory antibody response to the encapsulated protein (at approximately 300 days) after only two initial immunizations (days 0 and 14). This correlated with increased antigen-specific cell cycling of CD4(+) T cells: increase in synthetic (S) and mitotic (G(2)/M) and decrease in resting (G(1)) phases. Thus, archaeosomes may be potent vaccine carriers capable of facilitating strong primary and memory humoral, and cell-mediated immune responses to the entrapped antigen. (+info)
Impaired affinity maturation in Cr2-/- mice is rescued by adjuvants without improvement in germinal center development.
Cr2-/- mice have an impairment in humoral immunity, as shown by the decrease in the Ab titers against T cell-dependent Ags and abnormalities in germinal center formation. Germinal centers are present, but they are decreased in size and number, indicating problems in their development. In this study, we investigated whether this abnormality in germinal center development is associated with problems in the establishment of optimal affinity maturation and the generation of memory B cells, processes closely related to the germinal center reaction. We immunized the Cr2-/- animals with different Ags with or without adjuvants. We showed that, when immunized without adjuvants, complement receptors are absolutely required for optimal affinity maturation. Although limited affinity maturation is elicited in the Cr2-/- Ab response, it is decreased as compared with normal animals. Memory B cell generation is also impaired. In the presence of adjuvants, germinal center development in the Cr2-/- mice is still abnormal, as demonstrated by their decreased size and number. Surprisingly, adjuvants establish optimal affinity maturation and partially restore the amount of Ab produced during the primary response and memory B cell generation. However, adjuvants cannot improve the ability of follicular dendritic cells to retain Ags in the form of immune complexes. These observations indicate that immunization with inflammatory Ags offset some of the immunological abnormalities found in the Cr2-/- mice and show that optimal affinity maturation in the Cr2-/- mice can be achieved in the absence of normal germinal centers. (+info)
Calcium phosphate nanoparticle adjuvant.
Vaccination to protect against human infectious diseases may be enhanced by using adjuvants that can selectively stimulate immunoregulatory responses. In a murine model, a novel nanoparticulate adjuvant composed of calcium phosphate (CAP) was compared with the commonly used aluminum (alum) adjuvants for its ability to induce immunity to herpes simplex virus type 2 (HSV-2) and Epstein-Barr virus (EBV) infections. Results indicated that CAP was more potent as an adjuvant than alum, elicited little or no inflammation at the site of administration, induced high titers of immunoglobulin G2a (IgG2a) antibody and neutralizing antibody, and facilitated a high percentage of protection against HSV-2 infection. Additional benefits of CAP include (i) an insignificant IgE response, which is an important advantage over injection of alum compounds, and (ii) the fact that CAP is a natural constituent of the human body. Thus, CAP is very well tolerated and absorbed. These studies were performed with animal models. By virtue of the potency of this CAP adjuvant and the relative absence of side effects, we believe that this new CAP formulation has great potential for use as an adjuvant in humans. (+info)