Human chorionic gonadotropin (hCG), a hormone essential for pregnancy, is also ectopically expressed by a variety of cancers and is associated with poor prognosis; molecular mechanisms which may contribute to tumor progression remain ill-defined. Exogenous hCG enhanced the viability of human colorectal and lung cancer cells and promoted the growth of syngeneic tumors in mice. It induced the synthesis of VEGF, IL-8, matrix metalloprotease (MMP)-2 and MMP-9, and increased invasiveness in an MMP-dependent manner. While inducing the secretion of the tumor-associated extra-cellular matrix proteoglycan versican from tumor cells, hCG consequently caused the TLR-2-mediated generation of the inflammatory, tumor-associated cytokines TNF-α and IL-6 from peripheral blood adherent cells. The molecule up-modulated the Treg-associated transcription factor FOXP3 in tumor cells and increased the secretion of TGFβ and IL-10, thereby inhibiting T cell proliferation and inducing the differentiation FOXP3 CD4 CD25 cells into functional FOXP3 CD4 CD25 suppressor cells. Co-culture of hCG-treated tumor cells with mature bone-marrow derived dendritic cells induced the generation of active indoleamine deoxygenase. While anti-hCG antibodies restricted the growth of implanted tumor cells in nude mice, immunization of immune competent mice with a βhCG-TT conjugate supplemented with Mycobacterium indicus pranii provided synergistic survival benefit in animals implanted with syngeneic, hCG-responsive tumor cells. These studies elucidate the pathways by which hCG can promote tumorigenesis, providing further rationale for anti-hCG vaccination in the treatment of gonadotropin-sensitive tumors. © 2016 Wiley Periodicals, Inc.

Hemolysis-associated anemia is characteristic of diseases such as atherosclerosis, lupus, malaria, and leishmaniasis; the toxic effects of free hemoglobin (Hb) have been extensively described. This study was based on the premise that release of this sequestered, inflammatory molecule can result in deleterious immunological consequences, particularly in the context of pre-existing lupus. IgG anti-Hb responses were detected in the sera of lupus patients. Lupus-prone mice exhibited heightened plasma Hb levels, and ferric (Fe3+) Hb triggered preferential release of lupus-associated cytokines from splenocytes derived from aging lupus-prone mice. Anti-Hb B cell precursor frequencies were heightened in such mice, which also expressed increased titers of anti-Hb antibodies in serum and in kidney eluates. Fe3+ Hb preferentially increased the functional maturation of bone marrow-derived dendritic cells (BMDCs) from lupus-prone mice, effects abrogated upon the inhibition of Stat3. Hb interacted with lupus-associated autoantigens extruded during apoptosis and coincubation of Hb and apoptotic blebs had additional maturation-inducing effects on lupus BMDCs. Immunization with Hb in lupus-prone mice induced antigen spreading to lupus-associated moieties; Hb-interacting autoantigens were preferentially targeted and increased complement deposition and glomerulosclerosis were observed. Hb therefore demonstrates both antigenicity and immunogenicity and triggers specific immuno-pathological effects in a lupus milieu.

Human chorionic gonadotropin (hCG) prolongs the secretion of progesterone from the corpus luteum, providing a critical stimulus for the sustenance of pregnancy. hCG (or individual subunits) is also secreted by a variety of trophoblastic and non-trophoblastic cancers and has been associated with poor prognosis. Early clinical studies have indicated merit in anti-hCG vaccination as potential immunotherapy, but anti-tumor efficacy is believed to be compromised by sub-optimal immunogenecity. In the present study, enhanced tumorigenesis was observed when SP2/O cells were subcutaneously injected in either male or female BALB/c x FVB/JβhCG/- F1 transgenic mice, establishing the growth-promoting effects of the gonadotropin for implanted tumors in vivo. The utility of Mycobacterium indicus pranii (MIP) was evaluated, as an innate anti-tumor immunomodulator as well as adjuvant in mice. MIP elicited the secretion of the inflammatory cytokines IFNγ, IL-6, IL-12p40, KC and TNFα from murine antigen presenting cells. When MIP was incorporated into an anti-hCG vaccine formulation previously employed in humans (a βhCG-TT conjugate adsorbed on alum), elevated T cell recall proliferative and cytokine responses to hCG, βhCG and TT were observed. MIP increased vaccine immunogenicity in mice of diverse genetic background (including in traditionally low-responder murine strains), leading to enhanced titres of bioneutralizing anti-hCG antibodies which exhibited cytotoxicity towards tumor cells. Individual administration of MIP and βhCG-TT to BALB/c mice subcutaneously implanted with SP2/O cells resulted in anti-tumor effects; significantly, immunization with βhCG-TT supplemented with MIP invoked synergistic benefits in terms of tumor volume, incidence and survival. The development of novel vaccine formulations stimulating both adaptive and innate anti-tumor immunity to induce collaborative beneficial effects may fill a niche in the adjunct treatment of hCG-sensitive tumors that are resistant to conventional therapy.

Immunopathological outcomes in Systemic Lupus Erythematosus (SLE; or lupus) are believed to be autoantibody-mediated. Conditions which promote a Th2 skew (such as pregnancy) should encourage antibody production, worsening antibody-mediated diseases while ameliorating Th1/Th17-mediated diseases. Although an increased propensity toward autoreactivity can be observed in pregnant lupus patients and in pregnant lupus-prone mice, whether a unique human pregnancy-specific factor can contribute to such effects is unknown. This study assessed whether human chorionic gonadotropin (hCG, a pregnancy-specific hormone of diverse function) at physiological concentrations could mediate stimulatory influences on immune parameters in non-pregnant, lupus-prone mice, in light of the hormone's ameliorating effects on Th1-mediated autoimmunity in murine models. Results demonstrate that administration of hCG heightened global autoreactivity in such mice; antibodies to dsDNA, RNP68, Protein S, Protein C, β2-glycoprotein 1, and several phospholipids were enhanced, and hormone administration had adverse effects on animal survival. Specifically in splenic cell cultures containing cells derived from lupus-prone mice, hCG demonstrated synergistic effects with TLR ligands (up-modulation of costimulatory markers on B cells) as well as with TCR stimuli (enhanced proliferative responses, enhanced levels of cytokines, and the phosphorylation of p38). In both instances, enhanced synthesis of lupus-associated cytokines was observed, in addition to the heightened generation of autoantibodies reactive toward apoptotic blebs. These results suggest that selective transducive, proliferative, and differentiative effects of hCG on adaptive immune cells may drive autoreactive responses in a lupus environment, and may also potentially provide insights into the association between the presence of higher hCG levels (or the administration of hCG) with the presence (or appearance) of humoral autoimmunity.

Haemoglobin (Hb) has well-documented inflammatory effects and is normally efficiently scavenged; clearance mechanisms can be overwhelmed during erythrocyte lysis. Whether Hb is preferentially inflammatory in lupus and triggers broad antiself responses was assessed. Peripheral blood mononuclear cells (PBMCs) derived from SLE patients secreted higher levels of lupus-associated inflammatory cytokines when incubated with human Hb than did PBMCs derived from healthy donors, an effect negated by haptoglobin. Ferric murine Hb triggered the preferential release of lupus-associated cytokines from splenocytes, B cells, CD4 T cells, CD8 T cells and plasmacytoid dendritic cells isolated from ageing, lupus-prone NZM2410 mice, and also had mitogenic effects on B cells. Pull-downs, followed by mass spectrometry, revealed interactions of Hb with several lupus-associated autoantigens; co-incubation of ferric Hb with apoptotic blebs (structures that contain packaged autoantigens) revealed synergies-in terms of cytokine release and autoantibody production in vitro-that were also restricted to the lupus genotype. Murine ferric Hb activated multiple signalling pathways and, in combination with apoptotic blebs, preferentially triggered MAP kinase signalling specifically in splenocytes isolated from lupusprone mice. Infusion of murine ferric Hb into lupus-prone mice led to enhanced release of lupus-associated cytokines, the generation of a spectrum of autoantibodies and enhanced-onset glomerulosclerosis. Given that the biased recognition of ferric Hb in a lupus milieu, possibly in concert with lupus-associated autoantigens, triggers inflammatory responses and the generation of lupus-associated cytokines, and also stimulates the generation of potentially pathogenic lupus-associated autoantibodies, neutralization of Hb could have beneficial effects.