Migration of T cells from nearby inflammatory foci into antibody bound tissue: a relay of T cell and antibody actions in targeting native autoantigen

Selective antigen-specific CD4(+) T-cell, but not CD8(+) T- or B-cell, tolerance corrupts cancer immunotherapy

Self-tolerance, presumably through lineage-unbiased elimination of self-antigen-specific lymphocytes (CD4(+) T, CD8(+) T, and B cells), creates a formidable barrier to cancer immunotherapy. In contrast to this prevailing paradigm, we demonstrate that for some antigens, self-tolerance reflects selective elimination of antigen-specific CD4(+) T cells, but preservation of CD8(+) T- and B-cell populations. In mice, antigen-specific CD4(+) T-cell tolerance restricted CD8(+) T- and B-cell responses targeting the endogenous self-antigen guanylyl cyclase c (GUCY2C) in colorectal cancer. Although selective CD4(+) T-cell tolerance blocked GUCY2C-specific antitumor immunity and memory responses, it offered a unique solution to the inefficacy of GUCY2C vaccines through recruitment of self-antigen-independent CD4(+) T-cell help. Incorporating CD4(+) T-cell epitopes from foreign antigens into vaccines against GUCY2C reconstituted CD4(+) T-cell help, revealing the latent functional capacity of GUCY2C-specific CD8(+) T- and B-cell pools, producing durable antitumor immunity without autoimmunity. Incorporating CD4(+) T-cell epitopes from foreign antigens into vaccines targeting self-antigens in melanoma (Trp2) and breast cancer (Her2) produced similar results, suggesting selective CD4(+) T-cell tolerance underlies ineffective vaccination against many cancer antigens. Thus, identification of self-antigens characterized by selective CD4(+) T-cell tolerance and abrogation of such tolerance through self-antigen-independent T-cell help is essential for future immunotherapeutics.

Lineage-specific T-cell responses to cancer mucosa antigen oppose systemic metastases without mucosal inflammatory disease

Cancer mucosa antigens are emerging as a new category of self-antigens expressed normally in immunologically privileged mucosal compartments and universally by their derivative tumors. These antigens leverage the established immunologic partitioning of systemic and mucosal compartments, limiting tolerance opposing systemic antitumor efficacy. An unresolved issue surrounding self-antigens as immunotherapeutic targets is autoimmunity following systemic immunization. In the context of cancer mucosa antigens, immune effectors to self-antigens risk amplifying mucosal inflammatory disease promoting carcinogenesis. Here, we examined the relationship between immunotherapy for systemic colon cancer metastases targeting the intestinal cancer mucosa antigen guanylyl cyclase C (GCC) and its effect on inflammatory bowel disease and carcinogenesis in mice. Immunization with GCC-expressing viral vectors opposed nascent tumor growth in mouse models of pulmonary metastasis, reflecting systemic lineage-specific tolerance characterized by CD8(+), but not CD4(+), T-cell or antibody responses. Responses protecting against systemic metastases spared intestinal epithelium from autoimmunity, and systemic GCC immunity did not amplify chemically induced inflammatory bowel disease. Moreover, GCC immunization failed to promote intestinal carcinogenesis induced by germ-line mutations or chronic inflammation. The established role of CD8(+) T cells in antitumor efficacy, but CD4(+) T cells in autoimmunity, suggests that lineage-specific responses to GCC are particularly advantageous to protect against systemic metastases without mucosal inflammation. These observations support the utility of GCC-targeted immunotherapy in patients at risk for systemic metastases, including those with inflammatory bowel disease, hereditary colorectal cancer syndromes, and sporadic colorectal cancer.

Species-specific immune responses generated by histidyl-tRNA synthetase immunization are associated with muscle and lung inflammation

Evidence implicating histidyl-tRNA synthetase (Jo-1) in the pathogenesis of the anti-synthetase syndrome includes established genetic associations linking the reproducible phenotype of muscle inflammation and interstitial lung disease with autoantibodies recognizing Jo-1. To better address the role of Jo-1-directed B and T cell responses in the context of different genetic backgrounds, we employed Jo-1 protein immunization of C57BL/6 and NOD congenic mice. Detailed analysis of early antibody responses following inoculation with human or murine Jo-1 demonstrates remarkable species-specifity, with limited cross recognition of Jo-1 from the opposite species. Complementing these results, immunization with purified peptides derived from murine Jo-1 generates B and T cells targeting species-specific epitopes contained within the amino terminal 120 amino acids of murine Jo-1. The eventual spreading of B cell epitopes that uniformly occurs 8 weeks post immunization with murine Jo-1 provides additional evidence of an immune response mediated by autoreactive, Jo-1-specific T cells. Corresponding to this self-reactivity, mice immunized with murine Jo-1 develop a striking combination of muscle and lung inflammation that replicates features of the human anti-synthetase syndrome.

Immunogenicity of four complementary deoxyribonucleic acid fragments from rabbit zona pellucida 3 and their effects on fertility

OBJECTIVE

To evaluate the exact region in different exons of rabbit zona pellucida (ZP)3 involved in recognition and binding between sperm and the ZP.

DESIGN

Prospective study of a female immunocontraceptive.

SETTING

State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences.

ANIMAL(S)

BALB/C mice.

INTERVENTION(S)

Immunization recombinant vaccines.

MAIN OUTCOME MEASURE(S)

Oocyte immunofluorescence and immunohistochemistry.

RESULT(S)

The immunogenicity and effects on fertility of these four fragments we used were different. Except for the ZP domain, the other three fragments of rabbit ZP3 may be useful as antigen to elicit antibodies. Antiserum was specific and obvious. The fertility of mice after immunization decreased slightly compared with the control.

CONCLUSION(S)

The most effective fragment that is associated with the sperm binding was from sequences contained in exons 5-8 or oligosaccharide linked to this region. Exons 5-8 or oligosaccharide linked to this region may exist outside of the ZP matrix and be safe for use as the antigen. The ZP domain may be not related to the recognition and binding.

Evaluation of the Contraceptive Potential of brZPCp Vaccine in BALB/c Mice: Their Safety and Efficacy

In this study we have examined the potential ability of Microtus branditi partial ZPC (brZPCp) cDNA sequence (436-1150 nt) as a target for immunocontraception. Immunogenicity studies and fertility trials were performed in BALB/c mice using recombinant construction pCR3.1-brZPC(p). ELISA outcome indicated that antibodies could be generated by immunized mice, and IgG titer was increased compared to the control. Immunohistochemistry outcome indicated that antibodies could recognize native ZP in vivo, which in turn, prevented the binding of sperm to ovulated eggs. Antibodies could also recognize recombinant protein expressed by BL21 in vitro, which was confirmed by SDS-PAGE and Western blot. Fertility rate was reduced by 45% compared to the control immunized with pCR3.1. Meanwhile, there was no incidence of significant ovarian pathology in treated mice. This experiment indicates that this vaccine can elicit the specific antibody which binds exactly to the corresponding ZPC. This construction is proved to be immunogenic, and can reduce fertility without obvious oophoritis. The result in this study suggests a potentially important method for controlling population for its safety and easy production.

Transient expression of CC chemokine TECK in the ovary during ovulation: its potential role in ovulation

PROBLEM

Chemokine thymus-expressed chemokine (TECK), which is expressed exclusively in the thymus and small intestine, plays a critical role in T-cell development. Our previous study revealed its expression in the ovary also. This study investigated its ovarian expression during ovulatory process.

METHOD OF STUDY

Super-ovulation was induced in young female CD1 mice by equine chorionic gonadotropin (eCG) and human chorionic gonadotropic (hCG). Ovarian TECK expression during ovulation was determined by: (1) reverse transcriptase-polymerase chain reaction (RT-PCR) at mRNA level, (2) Western blot and immunohistology at the protein level, and (3) leukocyte infiltration assay at the bioactive level.

RESULTS

A transient, high-level expression of TECK in murine ovaries at the mRNA level during hCG-induced ovulation was detected. Sequencing of directly cloned PCR product confirmed the ovarian expression of TECK. The peak expression of TECK was observed at 10-12 hr post-hCG injection; real-time PCR revealed an 800-fold increase during its expression peak over 0 hr. The expressed ovarian TECK protein was readily detectable by Western blot. Immunohistochemistry localized TECK expression to the ovarian interstitial tissue surrounding, or in the theca layer of the mature follicles undergoing ovulatory process. Expression of TECK receptor, the CC chemokine receptor (CCR9) was also detected in the ovulating ovaries. Using in vitro leukocyte infiltration assay, we first demonstrated that ovaries undergoing the ovulatory process were able to selectively chemoattract mononuclear cells. Importantly, neutralization of TECK by the antibody resulted in a 85% reduction in the chemotactic activities of the ovaries.

CONCLUSION

This study suggested that ovarian expression of TECK is under a tight hormonal regulation, and expressed TECK may be responsible for recruitment of mononuclear cells into the ovary to participate in the ovulatory process.

Contraception in mice immunized with recombinant zona pellucida subunit 3 proteins correlates with Th2 responses and the levels of interleukin 4 expressed by CD4+ cells

The immune responses and contraceptive effect in mice were tested following immunization with purified recombinant zona pellucida (ZP) proteins produced using a vaccinia (v) virus T7 mammalian expression system. Female BALB/c and CBA mice were immunized with recombinant mouse (m) ZP3 (vmZP3) or pig (p) ZPC (vpZPC) using Freund's adjuvants and boosted three times. Fertility and mean litter size were significantly reduced in groups of BALB/c mice immunized with recombinant vmZP3 and vpZPC compared with controls treated with Freund's adjuvants alone. In CBA mice, fertility and mean litter size were significantly reduced in groups of animals immunized with vmZP3 but not with vpZPC compared with the controls. Most infertile animals treated with vmZP3 and a single infertile BALB/c mouse treated with vpZPC lacked mature follicles in the ovaries, whilst no abnormalities were detected in the remaining vpZPC treated, fertile vmZP3 treated and control mice. All mice (both fertile and infertile) immunized with vmZP3 and vpZPC produced IgG antibodies, but the levels of total IgG, IgG1 and IgG2a did not correlate with infertility. All BALB/c and CBA mice immunized with vmZP3 and vpZPC showed greater delayed type hypersensitivity responses in the footpads after challenge with their respective antigens than controls, but these did not differ between the fertile and infertile mice. There was, however, a significant correlation between infertility and the levels of the Type 2 T helper cell (Th2) cytokine interleukin 4 produced by CD4+ cells from vmZP3 immunized mice in response to stimulation with vmZP3 and this did not apply to the levels of the Type 1 T helper cell (Th1) cytokine interferon gamma or the general proliferation response. The results support the conclusion that induction of Th2 responses in individual mice determines whether infertility develops in response to immunization with zona pellucida proteins.

Ovarian expression of chemokines and their receptors

Recent studies suggest involvement of the immune system, including leukocytes and cytokines/chemokines, in various ovarian functions such as ovulation. Using the RT-PCR method, we examined expression of various chemokines and their receptors in normal mouse ovaries. Among seventeen examined chemokines (17 CC types and two CXC types), expressions of CC types MCP-1 and RANTES, and CXC type IP-10 were detected at high levels, while most CC types expressed at variable or low levels. Only five chemokines were not detected in the ovary. We next examined expression of chemokine receptors. CCR1 and CCR2, which are the receptors for MCP-1 and RANTES, were also expressed at constitutively high levels while others were not detectable. We further showed that a significant part of expression of both detected chemokines and receptors originated from peripheral blood leukocytes (PBL) circulating in the ovary. However, ovarian tissue was the major contributor of expression. Constitutive expression of several chemokines and their receptors suggests frequent migrations/movements of leukocytes in the ovary, which may be involved in ovarian functions other than ovulation.

Development of mouse-specific contraceptive vaccines: infertility in mice immunized with peptide and polyepitope antigens

Mouse-specific immunocontraceptive peptides have been identified in mouse proteins with key roles in reproduction from sequence comparisons to other species and tested for efficacy as immunocontraceptive antigens. Peptides were derived from granulocyte-macrophage colony-stimulating factor (GMCSF), the placental 27 kDa heat-shock protein (HSP), leukemia inhibitory factor receptor (LIFR), oviduct glycoprotein (OGP), proliferin (PLF), prolactin (PRL), sperm protein SP56 and mouse zona pellucida subunits 1 and 3 (ZP1, ZP3). Fertility of female BALB/c mice was reduced after immunization with several peptides either conjugated to a carrier protein or in the form of recombinant polyepitopes. The most effective conjugated peptides (SP56, GMCSF and PRL) induced peptide-specific serum antibodies and reduced fertility by 50%. Fertility of mice was also reduced after immunization with polyepitope antigens containing up to five different peptides fused to maltose-binding protein, but antibodies were not produced against all the encoded peptides. The most effective polyepitope antigen (containing PLF, SP56, ZP1 and ZP3 peptides) reduced fertility by 50% but induced only SP56 and ZP1 antibodies. We demonstrate that lack of antibody response to a given peptide epitope (ZP3) can be overcome if repeated copies are used in the polyepitope antigen construct, but the effect varies between mouse strains. We conclude that infertility induced in mice with a range of peptide-based vaccines is dependent on antigen formulation and genetic factors but does not necessarily correlate with peptide-specific antibody levels. In light of these results, strategies to improve the efficacy of peptide-based antifertility vaccines are discussed.