Blood groups, disease, and selection

Fisetin protects against cardiac cell death through reduction of ROS production and caspases activity

Myocardial infarction (MI) is a leading cause of death worldwide. Reperfusion is considered as an optimal therapy following cardiac ischemia. However, the promotion of a rapid elevation of O₂ levels in ischemic cells produces high amounts of reactive oxygen species (ROS) leading to myocardial tissue injury. This phenomenon is called ischemia reperfusion injury (IRI). We aimed at identifying new and effective compounds to treat MI and minimize IRI. We previously studied heart regeneration following myocardial injury in zebrafish and described each step of the regeneration process, from the day of injury until complete recovery, in terms of transcriptional responses. Here, we mined the data and performed a deep in silico analysis to identify drugs highly likely to induce cardiac regeneration. Fisetin was identified as the top candidate. We validated its effects in an in vitro model of MI/IRI in mammalian cardiac cells. Fisetin enhances viability of rat cardiomyocytes following hypoxia/starvation – reoxygenation. It inhibits apoptosis, decreases ROS generation and caspase activation and protects from DNA damage. Interestingly, fisetin also activates genes involved in cell proliferation. Fisetin is thus a highly promising candidate drug with clinical potential to protect from ischemic damage following MI and to overcome IRI.

Virus recognition by specific natural antibodies and complement results in MHC I cross-presentation

Natural antibodies (NAb) and complement (C’) are important regulators of immune system activation. We have shown previously that the galactosyl‐α1,3‐galactosyl (Galα1,3Gal) xenoantigen and the similar ABO histo‐blood group antigens are transferred onto virus from the producer cell, resulting in sensitisation of the virus to the respective NAb in a C’‐dependent manner. Here we show that measles virus (Mv) that expresses Galα1,3Gal termini can drive the proliferation of human T cells in the presence of serum and autologous DC, whereas without such targets, measles, as expected, suppress T cell reactivity. The use of affinity‐purified NAb to Galα1,3Gal and rabbit C’ demonstrated the components in human serum responsible for this effect. Proteasome inhibition and blocking of antigen presentation showed that the increased T cell proliferation was mediated by MHC class I cross‐presentation of immune complexes. These results lend further support to the idea that polymorphic carbohydrates of the Galα1,3Gal/ABO type serve as important targets for NAb and C’ and that their expression on virus has influenced their evolution by contributing to protection against viral transmission within as well as between species. The adjuvance effect of this recognition, acting as a bridge between the natural innate and adaptive immune systems, also has important implications for vaccine development.

Expression of ABO or related antigenic carbohydrates on viral envelopes leads to neutralization in the presence of serum containing specific natural antibodies and complement

No definitive biologic function has been associated with the human ABO histo-blood group polymorphism, or any other terminal carbohydrate differences within or between closely related species. We have experimentally addressed the question of whether viral particles can become glycosylated as determined by the glycosylation (eg, ABO) status of the producer cell and as a result be affected by human serum containing specific natural antibodies (NAbs). Measles virus was produced in cells transfected with cDNA encoding, either human A-transferase, B-transferase, an inactive "O-transferase," or a pig alpha1-3galactosyltransferase (alpha1-3GT) synthesizing the Galalpha1-3Gal structure. The viruses were shown to carry the same ABO structures as the cells; that is, A but not B if produced in A-type cells, and B but not A if produced in B-type cells. Only O was detected on the virus produced from O-type cells, whereas reduced amounts of O appeared on the A- and B-type viral particles. In addition, the Galalpha1-3Gal structure was transferred onto measles only when grown in human cells expressing this structure. When subjected to human preimmune sera, the A-type, the B-type, and the Galalpha1-3Gal viral particles were partially neutralized in a complement-dependent manner. However, the O-type or the Galalpha1-3Gal-negative viral particles were not neutralized. The neutralization appeared to be mediated by specific NAb, as judged by specific inhibition using synthetic A and Galalpha1-3Gal oligosaccharides. Such viral glycosylation may thus partly explain why the ABO antigens and other similar intraspecies as well as interspecies polymorphic carbohydrates have evolved and been maintained over long evolutionary periods.

Primate ABO glycosyltransferases: evidence for trans-species evolution

The human ABO blood group system is controlled by alleles at a single locus on chromosome 9. The alleles encode glycosyltransferases, which add different sugar residues to the terminal part of the oligosaccharide core, thus generating the A or B antigens; an allele encoding enzymatically inactive protein is responsible for the blood group O. The A and B antigens are present not only in humans, but also in many other primate species and it has been proposed that the AB polymorphism was established long before these species diverged. Here we provide molecular evidence for the trans-species evolution of the AB polymorphism. Polymerase-chain reaction (PCR) amplification and sequencing has revealed that the critical substitutions differentiating the A and B genes occurred before the divergence of the lineages leading to humans, chimpanzees, gorillas, and orangutans. This polymorphism is therefore at least 13 million years old and is most likely maintained by selection. Comparison of the sequences derived from different species indicates that the difference in enzymatic activities between the A and B transferases is caused by two single nucleotide substitutions responsible for Leu-Met and Gly-Ala replacement at positions 265 and 267 in the polypeptide chains, respectively.

Relationship between infectious diseases and human blood type

During the past eight decades, a large number of studies have examined the possible relationship between blood type and infection. Many publications reflect uncritical attempts to mathematically link unstratified or random data. The interaction of pathogen and erythrocyte membrane may reflect antigenic similarity, adhesion through specific receptors, or modulation of antibody response. Anthropological surveys suggest that the geographic and racial distribution of human blood groups reflects susceptibility of populations with specific blood types to the plague, cholera, smallpox, malaria and other infectious diseases.

The relationship between epidemic influenza (A(H1N1) and ABO blood group

An outbreak of influenza caused by the A(H1N1) subtype in military recruits in February 1978 afforded an opportunity to study the association of ABO blood groups with influenza morbidity and serological response. Fifty-eight per cent of 336 recruits became clinically ill. There was no differential distribution of clinical influenza by blood group. However, seroconversion to a titre of greater than or equal to 20 was significantly and appreciably higher in groups A and B than O and AB. Also, among those with serologically confirmed clinical influenza, the occurrence was significantly higher in groups A and B than groups O and AB.

HLA antigens in chronic idiopathic pancreatitis compared with chronic alcoholic pancreatitis

HLA A and B antigens in 46 patients with chronic pancreatitis were studied in Japan. Patients were divided into the two groups according to the etiology of the disease: one was chronic idiopathic pancreatitis (18 cases) and the other was chronic alcoholic pancreatitis (28 cases). One hundred twenty unrelated subjects were also examined as control. HLA B5 was detected in 14 of 18 cases of chronic idiopathic pancreatitis, which was significantly higher statistically than in control (P less than 0.001, corrected P less than 0.05). In contrast, no HLA antigens of locus A and B were found which had a relationship to chronic alcoholic pancreatitis. These results suggest that some genetic factors may be implicated in the development of chronic idiopathic pancreatitis and differing from that of alcoholic pancreatitis.

Membrane glycoproteins shed in defence of the cells of the gastrointestinal tract

The cells lining the gastrointestinal tract are exposed to various potentially harmful agents, including plant lectins and microorganisms. It is proposed that glycoproteins within the mucus layer of the gut protect against these agents. A hypothesis is presented that membrane glycoproteins are shed and, within the mucus close to the cell surface, block the binding of lectins or attachment of microorganisms to membrane receptors. A model is presented that demonstrates that such blocking can be achieved by soluble glycoproteins. The implications of this hypothesis in health and disease are discussed.

Immunological cross-reactivity between a glycoprotein isolated from Trichophyton mentagrophytes and human isoantigen A

A glycoprotein isolated from the cell wall of Trichophyton mentagrophytes was assessed for its cross-reaction with human blood group isoantigens. Rabbit antiglycoprotein antibodies agglutinated human erythrocytes of blood groups A1 and A2, and precipitated Blood Group Substance A in agarose gels. Erythrocytes of blood group B were only slightly agglutinated, and O(Rho+) and O(Rho-) erythrocytes were not. Additionally, the glycoprotein was shown to specifically inhibit isoagglutination of erythrocytes of group A. Partial identity between the glycoprotein and a crude extract of the fungus was demonstrated by immunodiffusion. Analyses revealed the glycoprotein to be composed of approximately 17% protein and 80% carbohydrate. The glycoprotein was found by indirect immunofluorescence to be located in the mycelial cell wall. The possibility that cross-reacting antigens may lead to a chronic, spreading infection is discussed.

Ontogeny of the bovine immune response

The ontogenesis of the bovine immune response was studied in three embryos (<40 days) and 106 fetuses of various ages. In the absence of overt antigenic stimulation, fetuses had lymphoid development of the thymus at 42 days of gestation, the spleen was structurally present at 55 days, and certain peripheral lymph nodes were present at 60 days. Mesenteric lymph nodes were structurally present by 100 days of gestation, and lymphoid tissue of the gastrointestinal tract, particularly the lower ileum, was observed in histologic sections of a 175-day fetus with a bacterial infection. Pyroninophilic cells, plasma cells, and germinal centers were present in lymph node sections of antigenically stimulated fetuses. Lymphoid tissue developed more rapidly in fetuses with bacteria, viral antigens, or apparent maternal red-blood-cell antigens than in the normal fetus. Thymic and splenic indices reached maximal values in the 205- to 220-day fetal age group. Immunoglobulin M (IgM)-containing cells were first observed, by immunofluorescence, in a single fetus at 59 days of gestation. Immunoglobulin G (IgG)-containing cells were observed at 145 days of gestation in one fetus with a bacterial and viral infection. IgM-containing cells were observed in 36 fetuses and IgM and IgG cells were present in seven fetuses. Spleen, lymph nodes, thymus, bone marrow, and liver of one fetus from a dam with lymphosarcoma had immunoglobulin-containing cells. Hemal lymph nodes, blood (buffy coat), Peyer patches, and heart and lung sections from fetuses with immunoglobulin-containing cells in spleen or lymph node did not have immunoglobulin-containing cells. Antigens of the virus of bovine virus diarrhea-mucosal disease (BVD) were detected in one fetus, and antigens of infectious bovine rhinotracheitis (IBR) virus were detected in three fetuses; however, viruses were not isolated in primary bovine embryonic kidney cells. Two of the three fetuses with IBR virus antigens had neutralizing serum antibody titers to IBR virus. Bacteria including Escherichia coli, Lactobacillus sp. and Mima polymorpha var. oxidans were isolated from four fetuses. Antibodies that caused the agglutination of maternal red blood cells were present in 8 of 20 bovine fetal serum samples. The antibodies were 2-mercaptoethanol sensitive and partially heat resistant (56 C for 30 min). The ontogeny of the bovine immune response and human immune response were compared, and it was suggested that the similarities were primarily due to the two species having the same approximate gestation period of 280 days.

Antibodies of influenza viruses in military recruits from Argentina, Brazil and Colombia. Their relation to ABO blood group distribution

In a large-scale seroepidemiological study, the prevalence was determined of antibodies to influenza A viruses in the sera of military representative of the inhabited geographical regions of Argentina, Brazil and Colombia. The micro-haemagglutination-inhibition test was used against the Swine, PR/8, FM/1 and Asian antigenic strains. From each of the three recruit populations 500 sera were tested.Positive titres to the FM/1 and Asian strains were found in 72% and 80% respectively of the Colombian sera, in 56% and 69% of the Argentinian sera, and in 49% and 63% of the Brazilian sera. Of these 1500 sera, 5 were positive to the PR/8 strain and 2 to the Swine strain.This study also showed that there were highly significantly greater proportions of positive reactors to the FM/1 and Asian strains among persons of blood groups O and B than among those of blood group A in all three countries.