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PubMed1997

Differences in hypervariable region 1 quasispecies between immune complexed and non-immune complexed hepatitis C virus particles.

Antibody to the hypervariable region 1 of hepatitis C virus (HCV) is thought to have neutralizing activity. The complexity of hypervariable region 1 quasispecies was compared between immune complexed and non-immune complexed HCV particles. Immune complexes and non-immune complexes, including intact HCV virions, were separated by differential flotation centrifugation and immunoprecipitation, and immune complexes were observed in 9 of 11 patients with chronic hepatitis C. Considerable differences in both hypervariable region 1 quasispecies and predominant clones were demonstrated between immune complexes and non-immune complexes in 4 patients and not in 5 patients. These results suggest that the specificity of antibody to hypervariable region 1 is related to the formation of immune complexes and that escape mutants with highly different quasispecies are resistant to neutralization by antibody to hypervariable region 1.

Adult↗

PubMed1979

Host immune responses after administration of inactivated Venezuelan equine encephalomyelitis virus vaccines--III. Kinetics for neutralizing antibody immunoglobulin class responses in donors and adoptively-immunized recipients.

C57B16 mice were immunized with either live, attenuated TC-83 strain VEE virus vaccine or formalin-inactivated VEE vaccine combined with Bordetella pertussis. The kinetics of specific donor and adoptively-immunized recipient anti-VEE neutralizing antibody responses were studied. Donor mice immunized with either live or inactivated VEE virus vaccine combined with potent adjuvants develop specific anti-VEE IgM and IgG responses as early as 7 days post-immunization. Anti-VEE IgM antibody responses comprise the majority of anti-VEE neutralizing antibody at this early time period. By 14 to 21 days post-immunization, anti-VEE IgG responses predominated. When adoptively-immunized recipients were studied, the anti-VEE IgM to IgG predominance seen in donors early after administration was reversed, and for each time-period studied, recipients' serum anti-VEE antibody class responses consisted principally of IgG rather than IgM antibody. Since T-cells cooperation with B-cells is critical in the IgM-IgG antibody shift, these studies support the critical role T-cells exert in adoptive transfer in a murine model of experimental VEE infection. Furthermore, immunization with either live or inactivated VEE vaccine coupled to a potent adjuvant induce comparable donor and adoptively-immunized recipient anti-VEE antibody class responses.

Animals↗

PubMed1983

A bi-directional immune network mechanism: simultaneous induction of idiotype and anti-anti-idiotype in rabbits immunized with antibody to a common idiotypic specificity of anti-VHa2-allotype antibodies.

Recently, we identified a common idiotypic specificity (IdC) present on all of the allo and auto anti-VHa2-allotype antibodies tested. In this report, we immunized allotype-matched rabbits with anti-IdC Ab. When an a1a1 homozygote was immunized with anti-IdC Ab (also from an a1a1 rabbit), two distinct Ab populations were induced which were isolated through the use of immunoadsorbent column chromatography. One of these Ab populations, adsorbed to and eluted from an insolubilized a2 IgG column, was anti-VHa2-allotype Ab (Ab 1), which reacted with a2 Ig and inhibited the reaction between the a2 allotype and anti-VHa2-allotype Ab. The other Ab population, adsorbed to and eluted from an insolubilized immunogen anti-IdC column, was anti-anti-IdC Ab (Ab 3), which was specific for the immunogen anti-IdC Ab. In another experiment, when an a1a2 heterozygous rabbit was immunized with anti-IdC Ab, only the Ab 3 was induced, which appeared to be identical to the Ab 3 induced in the a1a1 rabbit. However, when the expression of the a2 allotype in an a1a2 heterozygous rabbit was suppressed and then this rabbit was immunized with anti-IdC Ab, both Ab 1 and Ab 3 were induced. These data indicate the occurrence of a bi-directional immune response within our immune network system. According to Jerne's network theory, Ab 3 appeared to be induced through a stimulation by the idiotope of the immunogen Ab 2, whereas Ab 1 appeared to be induced through a reverse stimulation by the paratope of the immunogen Ab 2. Furthermore, the production of Ab 1 in these rabbits exhibiting the bi-directional immune response was at least 3-5 times greater than that of Ab 3 production indicating that the response through the reverse stimulation appeared to be dominant. The importance of this bi-directional immune response is discussed in this paper.

Animals↗

PubMed1991

Secretory immune responses in the mouse vagina after parenteral or intravaginal immunization with an immunostimulating complex (ISCOM).

Immunostimulating complexes (ISCOMs) are subunit vaccines that are particularly effective in producing immunity against systemic viral infections, but their effectiveness against mucosal infections has received little attention. To study their ability to produce mucosal immune responses in the female reproductive tract, a model ISCOM was prepared containing sheep erythrocyte membrane proteins, and anti-erythrocyte IgA and IgG titres in mouse vaginal washings were measured after immunization at parenteral or local mucosal sites. The ISCOM was prepared by a modified procedure that resulted in incorporation of 10-15% of initial membrane protein compared with 1-5% previously reported. Electrophoretic analysis demonstrated that four out of five erythrocyte membrane proteins were incorporated into the ISCOM, and electron microscopic observations indicated that the ISCOM had a cage-like structure with a diameter of 40 nm, similar to previous ISCOMs. Immunization in the pelvic presacral space (p.s.-p.s.) stimulated significantly higher anti-erythrocyte IgA titres in vaginal fluid than were produced by intraperitoneal (i.p.-i.p.), subcutaneous (s.c.-s.c.), intravaginal (i.vag.-i.vag.), or i.p.-i.vag. immunizations with the same vaccine. Specific IgG titres were less dependent on the route of immunization, with p.s.-p.s., i.p.-i.p. and s.c.-s.c. administration all giving similar high titres while i.p.-i.vag. treatment induced lower titres. These observations using a model ISCOM indicate that mucosal immune responses against membrane proteins were elicited in the female reproductive tract, and that non-mucosal immunization in the pelvis was a more effective route of administration than local application of the ISCOM to the vaginal mucosa.

Adjuvants, Immunologic↗

PubMed1994

Characterization of immune response and duration of protection in buffaloes immunized with haemorrhagic septicaemia vaccines.

Two of the three buffaloes immunized with a non-adjuvanted broth bacterin were found to be protected against experimental challenge at 6 weeks but not at 3 months post-challenge. Similarly all buffaloes (4/4) immunized with alum-precipitated vaccine were protected at 6 months but only 1 of the 2 vaccinated animals were protected at 12 months post-immunization. On the other hand, buffaloes immunized with an oil adjuvant and a double emulsion vaccine were completely protected at 12 months post-immunization. Statistically significant differences between immunized versus non-immune animals became evident at 3 months post-immunization, although analysis of cumulative antibody titres of pre-challenge sera of vaccinated buffaloes surviving versus those succumbing to experimental challenge revealed significant by higher antibody titres in the former as compared to the latter group. These results suggested that there was a relationship between ELISA antibody titres and active protection in buffaloes. There also appeared to be a relationship between cutaneous delayed-type hypersensitivity and active protection in buffaloes. Preliminary analysis of the antibody isotype distribution in the pre-challenge sera of 2 buffaloes vaccinated with the oil adjuvant vaccine revealed predominance of IgG1 and IgG2 subclasses whose role in protection against haemorrhagic septicaemia was not eludicated.

Animals↗

PubMed2006

Non-MHC ligands for inhibitory immune receptors: novel insights and implications for immune regulation.

Regulation of cellular responses by inhibitory receptors is crucial for proper function of the immune system. The prototype inhibitory immune receptors are major histocompatibility complex (MHC) class I binding killer-Ig like receptors (KIRs) present on effector cells such as natural killer (NK) cells and effector T cells. However, the recent identification of non-MHC class I ligands for inhibitory immune receptors, such as KLRG1, KLRB1 and LAIR-1, indicates that also MHC class I-independent inhibitory immune receptors play crucial roles in inducing peripheral tolerance. The presence of these receptors on many other immune cell types besides effector cells suggests that tight regulation of cell activation is necessary in all facets of the immune response in both normal and diseased tissue. Here, we review novel insights and implications of non-MHC class I ligand binding to inhibitory immune receptors. We give an overview of the known ligand-receptor pairs by grouping the ligands according to their properties and discuss implications of these interactions for the maintenance of immune balance and for the defense against tumors and pathogens.

Animals↗

PubMed2005

A recombinant P4 protein of Haemophilus influenzae induces specific immune responses biologically active against nasopharyngeal colonization in mice after intranasal immunization.

Outer membrane protein P4, together with P6, is highly conserved among all typeable and nontypeable strains of Haemophilus influenzae (H. influenzae). Thus, the protein is an attractive antigen for the inclusion in a vaccine against nontypeable H. influenzae (NTHi). However, the ability of P4 to induce antibodies protective against NTHi infections is still controversial. In this study, we investigated the specific mucosal immune responses against NTHi induced by intranasal immunization with the lipidated form of recombinant P4 protein (rP4) and non-fatty acylated recombinant P6 protein (rP6) with or without cholera toxin (CT) in BALB/c mice model. Intranasal immunization with either rP4+CT, a mixture of rP4 and rP6+CT, or rP4 and rP6 without CT elicited anti-rP4 specific IgG antibody in serum of mice. Intranasal immunization with either rP4+CT or a mixture of rP4, rP6+CT elicited anti-rP4 specific IgA antibody in nasopharyngeal washing (NPW), while intranasal immunization with rP4 and rP6 without CT did not induced anti-rP4 specific IgA antibody responses in NPWs. Sera from mice intranasally immunized with rP4+CT and a mixture of rP4, rP6+CT also showed bactericidal activity. Significant clearance of NTHi in nasopharynx was seen 3 days after the inoculation of live NTHi in mice intranasally immunized with rP4+CT. The current findings suggested that P4 would be a useful antigen as the component of the vaccine to induce protective immune responses against NTHi. The use of an intranasal vaccine composed of the different surface protein antigens is an attractive strategy for the development of a vaccine against NTHi.

Adjuvants, Immunologic↗

PubMed2003

Morbidity does not influence the T-cell immune risk phenotype in the elderly: findings in the Swedish NONA Immune Study using sample selection protocols.

A critical issue in our understanding of ageing and the immune system refers to the health status of the population from which inferences are drawn. The commonly used SENIEUR protocol, selecting individuals representing 'normal ageing' has recently been under debate because a substantial amount of individuals with various health problems are excluded. The aim of the present study was to investigate the influence of morbidity on immune parameters and to evaluate the associations with the T-cell immune risk phenotype (IRP), related to cytomegalovirus (CMV) seropositivity by applying the SENIEUR protocol and the OCTO-Immune protocol in the unselected population based sample (n=138) of oldest-olds, participating in the Swedish NONA Immune Study. The SENIEUR protocol excluded over 90% of the sample whereas the OCTO-Immune protocol excluded almost 65% of the sample. Three independent groups, very healthy (SENIEUR), moderately healthy (OCTO-Immune) and frail (non-SENIEUR/non-OCTO-Immune) were created. Flow cytometry studies on lymphocyte sub-populations revealed no significant difference in CD4/CD8 ratio, CD3+CD4-CD8+, CD3+CD4+CD8-, CD8+CD57+CD28-, CD8+CD56+CD57- or CD8+CD56+CD57+ between the very healthy, moderately healthy and the frail subsamples. Our findings indicate that morbidity does not significantly influence the T-cell immune risk profile in the elderly, and we suggest the inclusion of broader samples in future immunogerontological studies.

Aged↗

PubMed2001

Rectal immunization with antigen-containing microspheres induces stronger Th2 responses than oral immunization: a new method for vaccination.

The rectum as an effective site for induction of systemic and local immunity has received little attention. Rectal immunization with microspheres-containing ovalbumin (MS-OVA) was tested for its ability to elicit systemic and mucosal immune responses. Rectal immunization with MS-OVA enhanced both Th2 dominant OVA-specific IgG levels in the serum and OVA-specific IgA levels in fecal extracts more prominently than did oral immunization. Cytokine analysis of CD4(+) T cells indicated a predominant induction of Th2-type responses compared to Th1-type responses following rectal immunization compared to oral immunization. These results demonstrate that rectal immunization with microspheres could be an effective new vaccination method.

Administration, Oral↗

PubMed2003

Transcriptional targeting of dendritic cells in gene gun-mediated DNA immunization favors the induction of type 1 immune responses.

Cutaneous dendritic cells (DC) are pivotal for the elicitation of antigen-specific immune responses following gene gun-mediated biolistic transfection of the skin. We transcriptionally targeted transgene expression to DC using vectors containing the murine fascin promoter (pFascin) to control antigen production and compared the immune response elicited with conventional DNA immunization using plasmid constructs with the ubiquitously active CMV promoter (pCMV). Biolistic transfection with pFascin initiated a marked type 1 immune response characterized by the occurrence of a large population of IFN-gamma-producing T helper (Th) cells in spleen and draining lymph nodes. Consistently, immunoglobulin production was dominated by IgG2a antibodies. In contrast, the humoral response after repeated administration of pCMV was strongly enhanced and characterized by a type 2-like isotype pattern (IgG1 > IgG2a). Cytokine production analysis in vitro indicated compartmentalization of the immune response, revealing large numbers of IL-4-producing Th cells in the lymph nodes and dominant presence of IFN-gamma-producing Th cells in the spleen. Biolistic transfection with pFascin, like immunization with pCMV, led to potent induction of cytotoxic T cells as was assessed by JAM test. Thus gene gun immunization with plasmids that focus transgene expression and antigen production specifically to DC propagates type 1-biased cellular immune responses.

Biolistics↗

PubMed2003

Better preserved immune responses after immunization with rgp 160 in HIV-1 infected patients treated with highly active antiretroviral therapy than in untreated patients with similar CD4 levels during at 2 years' follow-up.

OBJECTIVE: To study the impact of effective highly active antiretroviral therapy (HAART) on the preservation of long-term CD4 memory cells induced by vaccines in HIV-1-infected patients. METHODS: Thirty HIV-1-positive patients on HAART with undetectable viral load were randomized into three groups: 10 received HIV-1 rgp160 vaccine, 10 received tetanus vaccine and 10 patients were not immunized. As controls, 10 HIV-negative volunteers were immunized with tetanus vaccine. The results were compared with an rgp160 vaccine study performed before the era of HAART on patients with comparable CD4 levels. All patients were monitored for 2 years for T-cell proliferative responses, T-cell subset levels, serum IgG and viral load. RESULTS: After 1 year all patients immunized with rgp160 had strong T-cell responses to the rgp160 antigen. After 2 years this response was preserved in the HAART-treated group, but not in the rgp160 immunized non-HAART group, despite comparable CD4 levels. Recall effects of the CD4-specific responses towards other antigens were seen in the rgp160-immunized HAART group. CONCLUSION: Immunization with rpg 160 leads to positive effects on HIV-specific T-cell proliferative responses in patients both with and without HAART. Immune responses after immunization is better preserved in HAART-treated patients who have low viral amounts than in individuals with high viral load and no HAART despite comparable CD4 levels during 2 years' follow-up. Interruption of HAART with return of a high viral load might thus have negative effects on T-cell functions in the long term, even if CD4 levels are kept at clinically acceptable levels.

AIDS Vaccines↗

PubMed2002

Genetic immunization maps T cell (auto)immune responses to self antigens homologous to exogenous proteins.

Genetic immunization represents a new tool for investigating physiological and pathological immune responses. Here we used genetic immunization with naked DNA to study the immune relevance of aminoacid sequence homologies by evaluating the outcome of immunization to a viral protein homologous to an HLA molecule. The viral protein was Balf2, a protein of Epstein-Barr virus (EBV) that shares aminoacid sequence homology with the HLA allele DRB1*0801. After genetic immunization of BALB/c mice with a construct encoding Balf2, we analyzed T cell responses of immunized mice. We found that cross-reactive proliferative and cytotoxic responses were raised to the homologous sequence as expressed by HLA-DRB1*0801. Furthermore, preferential secretion of Th1-type pro-inflammatory cytokines occurred. This strategy can allow rapid screening of interactive immune networks involving aminoacid sequence homologies between organisms.

Amino Acid Sequence↗

PubMed1993

Immunization with live versus killed Salmonella typhimurium leads to the generation of an IFN-gamma-dominant versus an IL-4-dominant immune response.

The mechanisms responsible for differential commitment of effector T cells to the production of either the IL-4/5/10 group or to the IL-2/IFN-gamma group of lymphokines during an immune response have not yet been clearly elucidated. We have used Salmonella typhimurium as a model murine bacterial parasite in BALB/c mice for live-cell versus killed-cell immunization and looked at the immune response in terms of delayed type hypersensitivity (DTH), IgG subclass distribution in the serum antibody response, and antigen-specific T cell proliferation and lymphokine secretion. The results indicate that the two forms of immunogen induce qualitatively different immune responses. Intraperitoneal immunization with live bacteria induces an IFN-gamma-dominant immune response associated with a strong DTH reaction and relatively higher levels of specific antibodies belonging to the IFN-gamma-dependent IgG2a isotype rather than the IL-4-dependent IgG1 isotype. Immunization with heat-killed bacteria gives rise to an IL-4-dominated response that shows excellent proliferative capacities in vitro, with lower levels of DTH responses and comparatively high levels of specific antibodies of the IgG1 isotype. IL-2 production in the responses generated by the two modes of immunization, however, is not preferentially associated with IFN-gamma production, unlike the reported profiles of long-lived murine T cell clones in vitro.

Animals↗

PubMedDate not supplied

Enhanced immunity to breast cancer in mice immunized with fibroblasts transfected with a complementary DNA expression library from breast cancer cells: Enrichment of the vaccine for immunotherapeutic cells.

Breast cancer cells express an array of weakly immunogenic tumor-associated antigens (TAAs). Under appropriate circumstances, immunity to breast cancer can be induced, with potential benefits for patients with the disease. Here, we report a new cell-based vaccination strategy resulting in enhanced immunity to breast cancer in tumor-bearing mice. The strategy was designed to enrich the vaccine for highly immunogenic cells. The vaccine was prepared by transfer of unfractionated complementary DNA (cDNA) derived from a highly malignant breast neoplasm that arose spontaneously in a C3H/He mouse (SB5b) into an immunogenic fibroblast cell line. As the transferred cDNA spontaneously integrates into the genome of the recipient cells and is replicated as the cells divide, sufficient DNA to prepare the vaccine could be obtained from as few as 10(7) cells (4-mm tumor). Because only a small proportion of the transfected cell population was expected to have incorporated genes responsible for inducing immunity to the breast cancer, we devised a novel approach designed to enrich the transfected cell population for cells that induced immunity to the neoplasm. Aliquots of the transfected population were divided into small pools (initial inoculum = 4 x 10). Afterward, the cell number from each pool was allowed to expand in vitro. Pools containing greater numbers of immunogenic cells (identified by 2 independent assays) were subdivided for additional rounds of immune selection. Enhanced immunity to the neoplasm was detected in tumor-bearing mice treated solely by immunization with the enriched cell population. The immunity, mediated by CD8+ T cells, was sufficient to prolong the survival of mice with established breast cancer.

Animals↗

PubMed2004

Influenza virus: immunity and vaccination strategies. Comparison of the immune response to inactivated and live, attenuated influenza vaccines.

Influenza virus is a globally important respiratory pathogen which causes a high degree of morbidity and mortality annually. The virus is continuously undergoing antigenic change and thus bypasses the host's acquired immunity to influenza. Despite the improvement in antiviral therapy during the last decade, vaccination is still the most effective method of prophylaxis. Vaccination induces a good degree of protection (60-90% efficacy) and is well tolerated by the recipient. For those at risk of complications from influenza, annual vaccination is recommended due to the antigenic changes in circulating strains. However, there is still room for improvement in vaccine efficacy, long-lasting effect, ease of administration and compliance rates. The mucosal tissues of the respiratory tract are the main portal entry of influenza, and the mucosal immune system provides the first line of defence against infection. Secretory immunoglobulin A (SIgA) and IgM are the major neutralizing antibodies directed against mucosal pathogens. These antibodies work to prevent pathogen entry and can function intracellularly to inhibit replication of virus. This review describes influenza virus infection, epidemiology, clinical presentation and immune system response, particularly as it pertains to mucosal immunity and vaccine use. Specifically, this review provides an update of the current status on influenza vaccination and concentrates on the two main types of influenza vaccines currently in use, namely the cold-adapted vaccine (CAV) given intranasally/orally, and the inactivated vaccine (IV) delivered subcutanously or intramuscularly. The commercially available trivalent IV (TIV) elicits good serum antibody responses but induces poorly mucosal IgA antibody and cell-mediated immunity. In contrast, the CAV may elicit a long-lasting, broader immune (humoral and cellular) response, which more closely resembles natural immunity. The immune response induced by these two vaccines will be compared in this review.

Administration, Intranasal↗

PubMed1992

Mechanism of the protective immunity against murine typhoid: persistence of Salmonella L forms in the liver after immunization with live-cell vaccines.

Live-cell vaccines of Salmonella typhimurium, either a sub-lethal dose of a wild-type (strain LT2) or a high dose of its two-heptose Rd1 mutant (strain SL1004), induced acquired resistance to murine typhoid, which remained 180 days after immunization. Growth of S. typhimurium as a bacillary form ceased between days 30 and 60 of immunization, but L forms of this bacterium colonized the liver (the mean number of L forms in the liver: 600 L-forming units) even at 180 days post-immunization. In contrast, a high inoculum of either a Ra mutant (strain TV148) of strain LT2 or S. schottmülleri 8006 sharing the same O antigenic components with those of S. typhimurium induced only a short-lived protection in proportion to the number of L forms in the liver, and the protective immunity was lost before day 180. However, there was no significant difference in the salmonella-specific T-cell responses among groups of immunized mice on day 180 of immunization. A lethal infection with strain LT2 in mice which had been immunized 75 days previously with living cells of strain SL1004 resulted in a rapid clearance of the challenge inoculum, together with a rapid elevation of anti-S. typhimurium antibody responses. Thus, the present data suggest that the long-lived immunity conferred upon live S. typhimurium vaccines is attributable to the colonization of this bacterium in the liver as L forms and the ability to colonize the liver as L forms is independent of the chain length of salmonella O-antigens.

Animals↗

PubMed1996

In vivo protective anti-HIV immune responses in non-human primates through DNA immunization.

An effective immune response involves the specific recognition of and elimination of an infectious organism at multiple levels. In this context DNA immunization can present functional antigenic proteins to the host for recognition by all arms of the immune system, yet provides the opportunity to delete any genes of the infectious organism which code for antigens or pieces of antigens that may have deleterious effects. Our group has developed the use of nucleic acid immunization as a possible method of vaccination against Human immunodeficiency virus type 1 (HIV-1) [1,2,3,10,11,12]. Sera from non-human primates immunized with DNA vectors that express the envelope proteins from HIV-1 contain antibodies specific to the HIV-1 envelope. These sera also neutralize HIV-1 infection in vitro and inhibit cell to cell infection in tissue culture. Analysis of cellular responses is equally encouraging. T cell proliferation as well as cytotoxic T cell lysis of relevant env expressing target cells were observed. In addition, evidence that DNA vaccines are capable of inducing a protective response against live virus was demonstrated using a chimeric SIV/HIV (SHIV) challenge in vaccinated cynomologous macaques. We found that nucleic acid vaccination induced protection from challenge in one out of four immunized cynomolgus macaques and viral load was lower in the vaccinated group of animals versus the control group of animals. These data encouraged us to analyze this vaccination technique in chimpanzees, the most closely related animal species to man. We observed the induction of both cellular and humoral immune responses with a DNA vaccine in chimpanzees. These studies demonstrate the utility of this technology to induce relevant immune responses in primates which may ultimately lead to effective vaccines.

AIDS Vaccines↗

PubMed1978

Immunity to antigenically related salmonellae: effects of humoral factors on the bactericidal activity of normal and immune peritoneal exudate cells.

Immunity against Salmonella enteritidis and Listeria monocytogenes was studied by measuring in vitro the bactericidal activity of peritoneal exudate cells (PEC) of control (normal PEC) and S. typhi Ty2-immune (immune PEC) mice. Specific immune serum, anti-S. tyhphi Ty2, heat inactivated at 56 degrees C for 30 min, significantly inhibited the growth of S. enteritidis only with immune PEC. These opsonic factors had no effect upon the activity of normal PEC. That such inhibition could not be demonstrated in Listeria experiments, either with immune or normal PEC, suggests that S. enteritidis was specifically recognized, in vitro, by the thermostable opsonin anti-S. typhi Ty2 and that macrophages from immune PEC were more efficient in inhibiting bacterial growth than those from normal PEC. Thus, the interaction between macrophages and the microorganism seems to play an essential role in cell-mediated as well as humoral immunity.

Antibodies, Bacterial↗