Targeting immune checkpoints such as programmed cell death protein 1 (PD1), programmed cell death 1 ligand 1 (PDL1) and cytotoxic T lymphocyte antigen 4 (CTLA4) has achieved noteworthy benefit in multiple cancers by blocking immunoinhibitory signals and enabling patients to produce an effective antitumour response. Inhibitors of CTLA4, PD1 or PDL1 administered as single agents have resulted in durable tumour regression in some patients, and combinations of PD1 and CTLA4 inhibitors may enhance antitumour benefit. Numerous additional immunomodulatory pathways as well as inhibitory factors expressed or secreted by myeloid and stromal cells in the tumour microenvironment are potential targets for synergizing with immune checkpoint blockade. Given the breadth of potential targets in the immune system, critical questions to address include which combinations should move forward in development and which patients will benefit from these treatments. This Review discusses the leading drug targets that are expressed on tumour cells and in the tumour microenvironment that allow enhancement of the antitumour immune response.

Combination cancer immunotherapy and new immunomodulatory targets.

Background. Intrauterine transmission of cytomegalovirus (CMV) can occur whether a mother has prior immunity or acquires CMV for the first time during pregnancy. The degree of protection afforded an infected infant by the presence of antibody in the mother before conception is uncertain. Methods. We compared the outcomes of CMV-infected infants born to mothers who acquired primary CMV infection during pregnancy (primary-infection group) with those of CMV-infected infants born to mothers with immunity (recurrent-infection group). Screening for viruria identified 197 newborns with congenital CMV infection. Stored serum samples were used to categorize maternal infection as either primary or recurrent. We followed 125 infants from the primary-infection group and 64 from the recurrent-infection group. Serial medical, audiologic, psychometric, and eye examinations were used to identify sequelae of CMV infection. Results. Only infants in the primary-infection group had symptomatic CMV infection at birth...

The Outcome of Congenital Cytomegalovirus Infection in Relation to Maternal Antibody Status

Name Sequence Exon 2 mG6pc S 5’-TCCCTGTCACCTGTGAG-3’ Exon 5 mG6pc AS 5’-CACAAGAAGTCTTTGTAA-3’ Exon1 mG6pcS 5’-TTACCAAGACTCCCAGGACTG-3’ Exon2 mG6pcAS 5’-GAGCTGTTGCTGTAGTAGTCG-3’ Pck1S 5’-AGCCTTTGGTCAACAACTGG-3’ Pck1AS 5’-TGCCTTCGGGGTTAGTTATG-3’ GcgR S 5’-ACCCAACTATTGCTGGTTGC-3’ GcgR AS 5’-CCATGTTGTCATTGCTGGTC-3’ Hmgcs2 S 5’-CCGTATGGGCTTCTGTTCAG-3’ Hmgcs2 AS 5’-AGCTTTGTGCGTTCCATCAG-3’ mL19S 5’-AGAAGATTGACCGCCATAT-3’ mL19AS 5’-TTCGTGCTTCCTTGGTCTTAGA-3’ CRU G6pc S 5’-TTTGCTATTTTACGTAAATCACCCT-3’  CRU G6pc AS 5’-GTACCTCAGGAAGCTGCCA-3’ CRU Pck1 S 5’-GGCCTCCCAACATTCATTAAC-3’ CRU Pck1 AS 5’-GTAGCTAGCCCTCCTCGCTTTAA-3’ GRU G6pc S 5’-CACCCCTTAGCACTGTAAGCCGTGTG-3’ GRU G6pc AS 5’-GGATTCAGTCTGTAGGTCAACCTAGCCC-3’ GRU Pck1 S 5’-TGCAGCCAGCAACATATGAA-3’

Supplementary table 1

HLA-G is a molecule that was first known to confer protection to the fetus from destruction by the immune system of its mother, thus critically contributing to fetal-maternal tolerance. The first functional finding constituted the basis for HLA-G research and can be summarized as such: HLA-G, membrane-bound or soluble, strongly binds its inhibitory receptors on immune cells (NK, T, B, monocytes/dendritic cells), inhibits the functions of these effectors, and so induces immune inhibition. HLA-G function may therefore be beneficial because when expressed by a fetus or a transplant it protects them from rejection, or deleterious because when expressed by a tumor, it also protects it from antitumor immunity. This is the primary HLA-G function: that of a checkpoint molecule. Great work has been done in the past years to characterize HLA-G itself, its regulation, its functions and mechanisms of action, and its pathological relevance. We will review this here, focusing on transplantation and oncology because these pathological contexts have been studied the most and also because they best represent the two opposite sides of HLA-G: beneficial to be promoted, or deleterious to be blocked.

HLA-G: An Immune Checkpoint Molecule.

Regulation of experimental autoimmune encephalomyelitis by natural killer (NK) cells

Communication between embryo and maternal endometrium occurs during a specific time frame in which implantation is possible. Here we demonstrate for the first time that conditioned media from non-manipulated human embryos cultured in vitro for 3 days or up to the blastocyst stage contain extracellular vesicles (EVs) with a diameter of 50 to 200 nm and bearing the traditional microvesicle and exosome marker proteins CD63, CD9 and ALIX. The embryonic origin of these EVs has been confirmed by the presence of stemness gene transcripts and their enrichment in the non-classical HLA-G protein. NANOG and POU5F1 transcripts were shown to be contained in vesicles deriving from embryos at different stages of development. In line with a higher detection rate of the HLA-G protein in blastocysts compared to cleavage stage embryos, a significantly higher amount of HLA-G was found in vesicles accumulated in spent media from day 3 to day 5 of development compared to those isolated from the earlier stage. Uptake of dye-labeled embryo-derived EVs by human primary endometrial epithelial and stromal cells was also demonstrated with a fluorescence intensity signal significantly higher for cells treated with vesicles derived from blastocysts. Based on these findings, EV exchange may be suggested as an emerging way of communication at the maternal-fetal interface.

Secretome of in vitro cultured human embryos contains extracellular vesicles that are uptaken by the maternal side

Human leukocyte antigen (HLA)-G molecule, a non-classical HLA-Ib molecule, is less polymorphic when compared to classical HLA class I molecules. HLA-G was first detected on cytotrophoblast cells at the feto-maternal interface but its expression is prevalent during viral infections and several autoimmune diseases. . HLA-G gene is characterized by polymorphisms at the 3' untranslated region and 5’ upstream regulatory region that regulate its expression and are associated with autoimmune diseases and viral infection susceptibility, creating an unbalanced and pathologic environment. This review focuses on the role of HLA-G expression in autoimmune conditions and viral infections.

/pdf/hla-g-molecules-in-autoimmune-diseases-and-infections-8ykdgavwhk.pdf

HLA-G Molecules in Autoimmune Diseases and Infections.

Human leukocyte antigen-G (HLA-G) is a low polymorphic nonclassical HLA-I molecule restrictively expressed and with suppressive functions. HLA-G gene products are quite complex, with seven HLA-G isoforms, four membrane bound, and other three soluble isoforms that can suffer different posttranslational modifications or even complex formations. In addition, HLA-G has been described included in exosomes. In this review we will focus on HLA-G biochemistry with special emphasis to the mechanisms that regulate its expression and how the protein modifications affect the quantification in biological fluids.

/pdf/some-basic-aspects-of-hla-g-biology-2jew5euj3g.pdf

Some Basic Aspects of HLA-G Biology

(1) Background: Acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent for the coronavirus disease (COVID-19) that has led to a pandemic that began in March 2020. The role of the SARS-CoV-2 components on innate and adaptive immunity is still unknown. We investigated the possible implication of pathogen-associated molecular patterns (PAMPs)-pattern recognition receptors (PRRs) interaction. (2) Methods: We infected Calu-3/MRC-5 multicellular spheroids (MTCSs) with a SARS-CoV-2 clinical strain and evaluated the activation of RNA sensors, transcription factors, and cytokines/interferons (IFN) secretion, by quantitative real-time PCR, immunofluorescence, and ELISA. (3) Results: Our results showed that the SARS-CoV-2 infection of Calu-3/MRC-5 multicellular spheroids induced the activation of the TLR3 and TLR7 RNA sensor pathways. In particular, TLR3 might act via IRF3, producing interleukin (IL)-1α, IL-1β, IL-4, IL-6, and IFN-α and IFN-β, during the first 24 h post-infection. Then, TLR3 activates the NFκB transduction pathway, leading to pro-inflammatory cytokine secretion. Conversely, TLR7 seems to mainly act via NFκB, inducing type 1 IFN, IFN-γ, and IFN-λ3, starting from the 48 h post-infection. (4) Conclusion: We showed that both TLR3 and TLR7 are involved in the control of innate immunity during lung SARS-CoV-2 infection. The activation of TLRs induced pro-inflammatory cytokines, such as IL-1α, IL-1β, IL-4, and IL-6, as well as interferons. TLRs could be a potential target in controlling the infection in the early stages of the disease.

TLR3 and TLR7 RNA Sensor Activation during SARS-CoV-2 Infection.

Human leukocyte antigen-G (HLA-G) molecules are non-classical HLA class I antigens with an important role in pregnancy immune regulation and inflammation control. Soluble HLA-G proteins can be generated through two mechanisms: alternative splicing and proteolytic release, which is known to be metalloprotease mediated. Among this class of enzymes, matrix metalloproteinases (MMPs) might be involved in the HLA-G1 membrane cleavage. Of particular interest are MMP-2 and MMP-9, which regulate the inflammatory process by cytokine and chemokine modulation. We evaluated the effect of MMP-9 and MMP-2 on HLA-G1 membrane shedding. In particular, we analyzed the in vitro effect of these two gelatinases on the secretion of HLA-G1 via proteolytic cleavage in 221-G1-transfected cell line, in JEG3 cell line, and in peripheral blood mononuclear cells. The results obtained by both cell lines showed the role of MMP-2 in HLA-G1 shedding. On the contrary, MMP-9 was not involved in this process. In addition, we identified three possible highly specific cleavage sites for MMP-2, whereas none were detected for MMP-9. This study suggests an effective link between MMP-2 and HLA-G1 shedding, increasing our knowledge on the regulatory machinery beyond HLA-G regulation in physiological and pathological conditions.

Daria Bortolotti

Papers

Secretome of in vitro cultured human embryos contains extracellular vesicles that are uptaken by the maternal side

HLA-G Molecules in Autoimmune Diseases and Infections.

Some Basic Aspects of HLA-G Biology

TLR3 and TLR7 RNA Sensor Activation during SARS-CoV-2 Infection.

Matrix metalloproteinase-2 (MMP-2) generates soluble HLA-G1 by cell surface proteolytic shedding.