Fetal Macrophages Exposed to Salmonella Antigens Elicit Protective Immunity Against Overwhelming Salmonella Challenge in A Murine Model

Despite the evidence for fetal immunization following maternal infection, it remained a mystery how the fetal immune system was primed by vertically-transmitted pathogens or microbial antigens, especially before its full maturation. We previously demonstrated the capacity of fetal macrophages for endocytosing oncoprotein and allergens to bridge towards adaptive immunity in postnatal life. To investigate the immunological consequences of fetal contact with microbial antigens and the role of fetal macrophages in the defense against infection before T-cell development, we exposed gestational day 14 murine fetuses and their macrophages to flagellin and heat-killed Salmonella Typhimurium. Recipients with in utero exposure to Salmonella antigens or adoptive transfer of microbial antigen-loaded fetal macrophages were examined for immune responses to Salmonella antigens and resistance to virulent Salmonella challenge. Fetal exposure to microbial antigens or adoptive transfer of microbial antigen-loaded fetal macrophages could confer antigen-specific adaptive immunity. However, protective immunity against lethal Salmonella challenge was only granted to those receiving heat-killed Salmonella antigens, presenting as heightened recall responses of serum anti-lipopolysaccharide immunoglobulins and interferon-gamma. In immunized recipients surviving Salmonella challenge, their serum transfer to succeeding recipients provided immediate protection from lethal Salmonella challenge in preference to lymphocyte transfer, indicating a more active role of humoral immunity in the prevention of Salmonella invasiveness. Our study sheds insight on the role of fetal macrophages in immunogenicity to transplacental pathogens regardless of fetal lymphocyte maturity, paving the way for fetal macrophage therapies to enhance vaccine responsiveness or increase resistance to pathogenic microorganisms in perinatal life.

Proteogenomic analysis unveils the HLA Class I presented immunopeptidome in melanoma and EGFR mutant lung adenocarcinoma

Immune checkpoint inhibitor and adoptive lymphocyte transfer-based therapies have shown great therapeutic potential for cancers with high tumor mutation burden (TMB). Here, we employed mass spectrometry (MS)-based proteogenomic large-scale profiling to identify potential immunogenic human leukocyte antigen (HLA) Class I-presented peptides in both melanoma, a “hot tumor” with high TMB, and EGFR mutant lung adenocarcinoma, a “cold tumor” with low TMB. We identified several classes of neopeptides, including mutated neoantigens and more than 1000 post-translationally modified peptides representing 58 different PTMs. We constructed a cancer germline (CG) antigen database with 285 antigens and identified 42 Class I-presented CG antigens. Finally, we developed a non-canonical peptide discovery pipeline to identify 44 lncRNA-derived peptides and validated Class I binding for select neopeptides. We provide direct evidence of HLA Class I presentation of a large number of neopeptides for potential vaccine or adoptive cell therapy in melanoma and mutant EGFR lung cancer.

Effect of neoantigen reactive T cells combined with chemotherapy and radiation on survival in advanced pancreatic cancer.

e15756 Background: Pancreatic cancer (PC) is one of the most aggressive and death-relating malignancy. Gemcitabine (GEM) is the key agent in the first-line standard regimen for advanced PC, which is mostly diagnosed at advanced stage and unsuitable for curative resection. The objective responsive rate (ORR) and medium progression free survival (PFS) of various GEM-based regimens are still unsatisfied. Therefore, development of new therapeutic modalities, including immunotherapy, is needed. This study is to investigate the efficacy, safety and clinical beneficial of combination neoantigen based immunotherapy with GEM and radiotherapy in locally advanced and metastatic PC patients. Methods: Three locally advanced unresectable and seven metastatic PC patients received at least two cycles of GEM (1000mg/m2 on day 1 and day 6), radiotherapy combing with neoantigen induced DC vaccination on day 7 and cytotoxic T lymphocyte transfer from day 12 to 15 (repeated every 21 days). The locally advanced unresectable PC patients received stereotactic body radiotherapy (SBRT) with a total amount of 50-66Gy during the first cycle. For metastatic patients, their partial lesions received a low dose radiation (0.5Gy bid*2days ) on day 10 and 11 in each cycle. Results: Two cases were observed with partial remission (PR), five with stable disease (sd), and three with progressive disease (PD). The disease control rate (DCR) was 70%. Median progression free survival (PFS) was 6.4 months. After the first treatment cycle, the total effectiveness for pain easement and increasing appetite are 100% (8/8)and 66.7%, respectively. Haematotoxicities with a 40% incidence rate were the most common adverse drug reactions. Two patients had grade 1 to 2 neutropenia, two with grade 3 to 4 thrombocytopenia. Three patients suffered grade 1 to 2 gemcitabine-induced skin rash. No treatment-related mortality occurred. Conclusions: Neoantigen reactive T cells combined chemoradiotherapy demonstrated an acceptable response and safety in advanced pancreatic cancer patients.

Validation of bovine glycomacropeptide as an intestinal anti-inflammatory nutraceutical in the lymphocyte-transfer model of colitis

Milk κ-casein-derived bovine glycomacropeptide (GMP) exerts immunomodulatory effects. It exhibits intestinal anti-inflammatory activity in chemically induced models of colitis. However, to validate its clinical usefulness as a nutraceutical, it is important to assess its effects in a model with a closer pathophysiological connection with human inflammatory bowel disease. Therefore, in the present study, we used the lymphocyte-transfer model of colitis in mice and compared the effects of GMP in this model with those obtained in the dextran sulphate sodium (DSS) model. GMP (15 mg/d) resulted in higher body-weight gain and a reduction of the colonic damage score and myeloperoxidase (MPO) activity inRag1− / −mice with colitis induced by the transfer of naïve T cells. The colonic and ileal weight:length ratio was decreased by approximately 25 %, albeit non-significantly. GMP treatment reduced the percentage of CD4+interferon (IFN)-γ+cells in mesenteric lymph nodes (MLN). The basal production of IL-6 by MLN obtained from the GMP-treated miceex vivowas augmented. However, concanavalin A-evoked production was similar. The colonic expression of regenerating islet-derived protein 3γ, S100A8, chemokine (C-X-C motif) ligand 1 and IL-1β was unaffected by GMP, while that of TNF-α and especially IFN-γ was paradoxically increased. In the DSS model, GMP also reduced the activity of colonic MPO, but it failed to alter weight gain or intestinal weight:length ratio. GMP augmented the production of IL-10 by MLN cells and was neutral towards other cytokines, except exhibiting a trend towards increasing the production of IL-6. The lower effect was attributed to the lack of the effect of GMP on epithelial cells. In conclusion, GMP exerts intestinal anti-inflammatory effects in lymphocyte-driven colitis.