Extent of the protection afforded by histo-blood group polymorphism against rotavirus gastroenteritis in metropolitan France and French Guiana.

Human rotaviruses attach to histo-blood group antigens glycans and null alleles of the ABO, FUT2 and FUT3 genes seem to confer diminished risk of gastroenteritis. Yet, the true extent of this protection remains poorly quantified. Here, we conducted a prospective study to evaluate the risk of consulting at the hospital in non-vaccinated pediatric patients according to the ABO, FUT2 (secretor) and FUT3 (Lewis) polymorphisms, in Metropolitan France and French Guiana. At both locations, P genotypes were largely dominated by P [8]-3, with P [6] cases exclusively found in French Guiana. The FUT2 null (nonsecretor) and FUT3 null (Lewis negative) phenotypes conferred near full protection against severe gastroenteritis due to P [8]-3 strains (OR 0.03, 95% CI [0.00-0.21] and 0.1, 95% CI [0.01-0.43], respectively in Metropolitan France; OR 0.08, 95% CI [0.01-0.52] and 0.14, 95%CI [0.01-0.99], respectively in French Guiana). Blood group O also appeared protective in Metropolitan France (OR 0.38, 95% CI [0.23-0.62]), but not in French Guiana. The discrepancy between the two locations was explained by a recruitment at the hospital of less severe cases in French Guiana than in Metropolitan France. Considering the frequencies of the null ABO, Secretor and Lewis phenotypes, the data indicate that in a Western European population, 34% (95% CI [29%; 39%]) of infants are genetically protected against rotavirus gastroenteritis of sufficient severity to lead to hospital visit.

Microbiota-induced regulatory T cells associate with FUT2-dependent susceptibility to rotavirus gastroenteritis.

The FUT2 α1,2fucosyltransferase contributes to the synthesis of fucosylated glycans used as attachment factors by several pathogens, including noroviruses and rotaviruses, that can induce life-threatening gastroenteritis in young children. FUT2 genetic polymorphisms impairing fucosylation are strongly associated with resistance to dominant strains of both noroviruses and rotaviruses. Interestingly, the wild-type allele associated with viral gastroenteritis susceptibility inversely appears to be protective against several inflammatory or autoimmune diseases for yet unclear reasons, although a FUT2 influence on microbiota composition has been observed. Here, we studied a cohort of young healthy adults and showed that the wild-type FUT2 allele was associated with the presence of anti-RVA antibodies, either neutralizing antibodies or serum IgA, confirming its association with the risk of RVA gastroenteritis. Strikingly, it was also associated with the frequency of gut microbiota-induced regulatory T cells (Tregs), so-called DP8α Tregs, albeit only in individuals who had anti-RVA neutralizing antibodies or high titers of anti-RVA IgAs. DP8α Tregs specifically recognize the human symbiont Faecalibacterium prausnitzii, which strongly supports their induction by this anti-inflammatory bacterium. The proportion of F. prausnitzii in feces was also associated with the FUT2 wild-type allele. These observations link the FUT2 genotype with the risk of RVA gastroenteritis, the microbiota and microbiota-induced DP8α Treg cells, suggesting that the anti-RVA immune response might involve an induction/expansion of these T lymphocytes later providing a balanced immunological state that confers protection against inflammatory diseases.

FUT2, Secretor Status and FUT3 Polymorphisms of Children with Acute Diarrhea Infected with Rotavirus and Norovirus in Brazil.

Host susceptibility according to human histo-blood group antigens (HBGAs) is widely known for norovirus infection, but is less described for rotavirus. Due to the variable HBGA polymorphism among populations, we aimed to evaluate the association between HBGA phenotypes (ABH, Lewis and secretor status) and susceptibility to rotavirus and norovirus symptomatic infection, and the polymorphisms of FUT2 and FUT3, of children from southeastern Brazil. Paired fecal-buccal specimens from 272 children with acute diarrhea were used to determine rotavirus/norovirus genotypes and HBGAs phenotypes/genotypes, respectively. Altogether, 100 (36.8%) children were infected with rotavirus and norovirus. The rotavirus P[8] genotype predominates (85.7%). Most of the noroviruses (93.8%) belonged to genogroup II (GII). GII.4 Sydney represented 76% (35/46) amongst five other genotypes. Rotavirus and noroviruses infected predominantly children with secretor status (97% and 98.5%, respectively). However, fewer rotavirus-infected children were Lewis-negative (8.6%) than the norovirus-infected ones (18.5%). FUT3 single nucleotide polymorphisms (SNP) occurred mostly at the T59G > G508A > T202C > C314T positions. Our results reinforce the current knowledge that secretors are more susceptible to infection by both rotavirus and norovirus than non-secretors. The high rate for Lewis negative (17.1%) and the combination of SNPs, beyond the secretor status, may reflect the highly mixed population in Brazil.

Host-Range Shift Between Emerging P[8]-4 Rotavirus and Common P[8] and P[4] Strains.

In Tunisia, we observed that rotavirus P[8]-3 and P[4] strains in young children with gastroenteritis associate with secretor histo-blood group phenotype. In contrast, the emerging P[8]-4 strain, representing 10% of cases, was exclusively found in nonsecretor patients. Unlike VP8* from P[8]-3 and P[4] strains, the P[8]-4 VP8* protein attached to glycans from saliva samples regardless of the donor's secretor status. Interestingly, a high frequency of FUT2 enzyme deficiency (nonsecretor phenotype) was observed in the population. This may allow cocirculation of P[8]-3 and P[8]-4 strains in secretor and nonsecretor children, respectively.

Histo-blood group antigen-binding specificities of human rotaviruses are associated with gastroenteritis but not with in vitro infection.

Human strains of rotavirus A (RVAs) recognize fucosylated glycans belonging to histo-blood group antigens (HBGAs) through their spike protein VP8*. Lack of these ligands due to genetic polymorphisms is associated with resistance to gastroenteritis caused by P[8] genotype RVAs. With the aim to delineate the contribution of HBGAs in the process, we analyzed the glycan specificity of VP8* proteins from various P genotypes. Binding to saliva of VP8* from P[8] and P[4] genotypes required expression of both FUT2 and FUT3 enzymes, whilst binding of VP8* from the P[14] genotype required FUT2 and A enzymes. We further defined a glycan motif, GlcNAcß3Galß4GlcNAc, recognized by P[6] clinical strains. Conversion into Lewis antigens by the FUT3 enzyme impaired recognition, explaining their lower binding to saliva of Lewis positive phenotype. In addition, the presence of neutralizing antibodies was associated with the presence of the FUT2 wild type allele in sera from young healthy adults. Nonetheless, in vitro infection of transformed cell lines was independent of HBGAs expression, indicating that HBGAs are not human RV receptors. The match between results from saliva-based binding assays and the epidemiological data indicates that the polymorphism of human HBGAs controls susceptibility to RVAs, although the exact mechanism remains unclear.

Host-Specific Glycans Are Correlated with Susceptibility to Infection by Lagoviruses, but Not with Their Virulence.

Rabbit hemorrhagic disease virus (RHDV) and European brown hare syndrome virus (EBHSV) are two lagoviruses from the family Caliciviridae that cause fatal diseases in two leporid genera, Oryctolagus and Lepus, respectively. In the last few years, several examples of host jumps of lagoviruses among leporids were recorded. In addition, a new pathogenic genotype of RHDV emerged, and many nonpathogenic strains of lagoviruses have been described. The molecular mechanisms behind host shifts and the emergence of virulence are unknown. Since RHDV uses glycans of the histo-blood group antigen type as attachment factors to initiate infection, we studied if glycan specificities of the new pathogenic RHDV genotype, nonpathogenic lagoviruses, and EBHSV potentially play a role in determining the host range and virulence of lagoviruses. We observed binding to A, B, or H antigens of the histo-blood group family for all strains known to primarily infect European rabbits (Oryctolagus cuniculus), which have recently been classified as GI strains. However, we could not explain the emergence of virulence, since similar glycan specificities were found in several pathogenic and nonpathogenic strains. In contrast, EBHSV, recently classified as GII.1, bound to terminal ß-linked N-acetylglucosamine residues of O-glycans. Expression of these attachment factors in the upper respiratory and digestive tracts in three lagomorph species (Oryctolagus cuniculus, Lepuseuropaeus, and Sylvilagus floridanus) showed species-specific patterns regarding susceptibility to infection by these viruses, indicating that species-specific glycan expression is likely a major contributor to lagovirus host specificity and range.IMPORTANCE Lagoviruses constitute a genus of the family Caliciviridae comprising highly pathogenic viruses, RHDV and EBHSV, that infect rabbits and hares, respectively. Recently, nonpathogenic strains were discovered and new pathogenic strains have emerged. In addition, host jumps between lagomorphs have been observed. The mechanisms responsible for the emergence of pathogenicity and host species range are unknown. Previous studies showed that RHDV strains attach to glycans expressed in the upper respiratory and digestive tracts of rabbits, the likely portals of virus entry. Here, we studied the glycan-binding properties of novel pathogenic and nonpathogenic strains looking for a link between glycan binding and virulence or between glycan specificity and host range. We found that glycan binding did not correlate with virulence. However, expression of glycan motifs in the upper respiratory and digestive tracts of lagomorphs revealed species-specific patterns associated with the host ranges of the virus strains, suggesting that glycan diversity contributes to lagovirus host ranges.

Neofunctionalization of the Sec1 α1,2fucosyltransferase paralogue in leporids contributes to glycan polymorphism and resistance to rabbit hemorrhagic disease virus.

RHDV (rabbit hemorrhagic disease virus), a virulent calicivirus, causes high mortalities in European rabbit populations (Oryctolagus cuniculus). It uses α1,2fucosylated glycans, histo-blood group antigens (HBGAs), as attachment factors, with their absence or low expression generating resistance to the disease. Synthesis of these glycans requires an α1,2fucosyltransferase. In mammals, there are three closely located α1,2fucosyltransferase genes rSec1, rFut2 and rFut1 that arose through two rounds of duplications. In most mammalian species, Sec1 has clearly become a pseudogene. Yet, in leporids, it does not suffer gross alterations, although we previously observed that rabbit Sec1 variants present either low or no activity. Still, a low activity rSec1 allele correlated with survival to an RHDV outbreak. We now confirm the association between the α1,2fucosyltransferase loci and survival. In addition, we show that rabbits express homogenous rFut1 and rFut2 levels in the small intestine. Comparison of rFut1 and rFut2 activity showed that type 2 A, B and H antigens recognized by RHDV strains were mainly synthesized by rFut1, and all rFut1 variants detected in wild animals were equally active. Interestingly, rSec1 RNA levels were highly variable between individuals and high expression was associated with low binding of RHDV strains to the mucosa. Co-transfection of rFut1 and rSec1 caused a decrease in rFut1-generated RHDV binding sites, indicating that in rabbits, the catalytically inactive rSec1 protein acts as a dominant-negative of rFut1. Consistent with neofunctionalization of Sec1 in leporids, gene conversion analysis showed extensive homogenization between Sec1 and Fut2 in leporids, at variance with its limited degree in other mammals. Gene conversion additionally involving Fut1 was also observed at the C-terminus. Thus, in leporids, unlike in most other mammals where it became extinct, Sec1 evolved a new function with a dominant-negative effect on rFut1, contributing to fucosylated glycan diversity, and allowing herd protection from pathogens such as RHDV.

A FUT2 gene common polymorphism determines resistance to rotavirus A of the P[8] genotype.

Attachment to carbohydrates of the histo-blood group type of several human Rotavirus strains (RVA) has recently been described. Synthesis of these ligands requires a functional FUT2 enzyme, suggesting that FUT2 null homozygote (ie, nonsecretor) individuals may not be recognized by most human RVA strains. Whereas such individuals represent 20% of the control population, this retrospective study determined that none of 51 patients infected by P[8] rotavirus strains were nonsecretors. The lack of α1,2fucosylated carbohydrate motifs in the gut surface mucosa is thus associated with resistance to symptomatic infection and virus attachment to such motifs is essential to the infection process.

Molecular characterization of noroviruses and HBGA from infected Quilombola children in Espirito Santo State, Brazil.

Noroviruses (NoV) are the main etiological agents of gastroenteritis outbreaks worldwide and susceptibility to NoV infection has been related to the histo-blood group antigen (HBGA). This study aimed to determine the prevalence of NoV strains and to evaluate the HBGA phenotype and genotype of children from semi-isolated Quilombola communities, descendents of black slaves in Brazil. A total of 397 children up to eleven years old, with and without diarrhea, from Quilombola Communities in the Espirito Santo State, Brazil, were investigated for the presence of NoV from August 2007 to September 2009. Feces were collected from all the children, and blood from the NoV positive children. NoV was screened by reverse transcription-PCR with primers for the RNA-dependent RNA polymerase region; genogroup was determined by PCR with primers for the C and D regions and genotyped by sequencing. HBGA phenotype was performed by gel-spinning and FUT2 and FUT3 were analyzed by PCR or sequencing analysis. NoV were detected in 9.2% (12/131) of diarrheic and 1.5% (4/266) of non-diarrheic children (p<0.05, Fisher's exact test). GI and GII genogroups were present in 12.5% and 87.5% of the samples, respectively. The following genotypes were characterized: GII.4 (25%), GII.12 (25%), GII.6 (12.5%) and GI.1 (6.3%), GI.3 (12.5%) and GI.4 (6.3%). Children infected with NoV showed the A (n = 6), O (n = 6), and B (n = 2) HBGA phenotypes, and 13 of them were classified as secretors (Se) and one as a non secretor (se). Mutations of Se (40), (171,216,357,428,739,960) were found for the FUT2 gene and mutations of Le (59, 202, 314) for the FUT3 gene. The only se child was infected by NoV GI, whereas the Se children were indiscriminately infected by GI or GII. This study showed rates of NoV infection in symptomatic and asymptomatic Quilombola children consistent with other studies. However, children under 12 months were seven times more affected than those between 1 and 5 years old. GII.12 was as frequent as GII.4 and GI.1 and GI.4 were described for the first time in Brazil. Owing to the small number of cases studied, no clear pattern of susceptibility and/or HBGA resistance could be inferred.

Histo-blood group antigens act as attachment factors of rabbit hemorrhagic disease virus infection in a virus strain-dependent manner.

Rabbit Hemorrhagic disease virus (RHDV), a calicivirus of the Lagovirus genus, and responsible for rabbit hemorrhagic disease (RHD), kills rabbits between 48 to 72 hours post infection with mortality rates as high as 50-90%. Caliciviruses, including noroviruses and RHDV, have been shown to bind histo-blood group antigens (HBGA) and human non-secretor individuals lacking ABH antigens in epithelia have been found to be resistant to norovirus infection. RHDV virus-like particles have previously been shown to bind the H type 2 and A antigens. In this study we present a comprehensive assessment of the strain-specific binding patterns of different RHDV isolates to HBGAs. We characterized the HBGA expression in the duodenum of wild and domestic rabbits by mass spectrometry and relative quantification of A, B and H type 2 expression. A detailed binding analysis of a range of RHDV strains, to synthetic sugars and human red blood cells, as well as to rabbit duodenum, a likely gastrointestinal site for viral entrance was performed. Enzymatic cleavage of HBGA epitopes confirmed binding specificity. Binding was observed to blood group B, A and H type 2 epitopes in a strain-dependent manner with slight differences in specificity for A, B or H epitopes allowing RHDV strains to preferentially recognize different subgroups of animals. Strains related to the earliest described RHDV outbreak were not able to bind A, whereas all other genotypes have acquired A binding. In an experimental infection study, rabbits lacking the correct HBGA ligands were resistant to lethal RHDV infection at low challenge doses. Similarly, survivors of outbreaks in wild populations showed increased frequency of weak binding phenotypes, indicating selection for host resistance depending on the strain circulating in the population. HBGAs thus act as attachment factors facilitating infection, while their polymorphism of expression could contribute to generate genetic resistance to RHDV at the population level.

Association between expression of the H histo-blood group antigen, alpha1,2fucosyltransferases polymorphism of wild rabbits, and sensitivity to rabbit hemorrhagic disease virus.

RHDV (rabbit hemorrhagic disease virus) is a highly virulent calicivirus that has become a major cause of mortality in wild rabbit populations (Oryctolagus cuniculus). It binds to the histo-blood group antigen (HBGA) H type 2 which requires an alpha1,2fucosyltransferase for its synthesis. In rabbit, three alpha1,2fucosyltransferases genes are known, Fut1, Fut2, and Sec1. Nonfunctional alleles at any of these loci could potentially confer resistance to RHDV, similar to human FUT2 alleles that determine the nonsecretor phenotype and resistance to infection by various NoV strains. In this study, we looked for the presence of H type 2 on buccal epithelial cells of wild rabbits from two geographic areas under RHDV pressure and from one RHDV-free area. Some animals with diminished H type 2 expression were found in the three populations (nonsecretor-like phenotype). Their frequency markedly increased according to the RHDV impact, suggesting that outbreaks selected survivors with low expression of the virus ligand. Polymorphisms of the Fut1, Fut2, and Sec1 coding regions were determined among animals that either died or survived outbreaks. The Fut2 and Sec1 genes presented a high polymorphism and the frequency of one Sec1 allele was significantly elevated, over 6-fold, among survivors. Sec1 enzyme variants showed either moderate, low, or undetectable catalytic activity, whereas all variant Fut2 enzymes showed strong catalytic activity. This functional analysis of the enzymes encoded by each Fut2 and Sec1 allele suggests that the association between one Sec1 allele and survival might be explained by a deficit of alpha1,2fucosyltransferase expression rather than by impaired catalytic activity.

Selection of high-avidity CD8 T cells correlates with control of hepatitis C virus infection.

UNLABELLED: Both strong antigenic avidity and acquisition of proper effector functions contribute to the efficacy of antiviral T cell responses. To correlate these parameters with the outcome of hepatitis C virus (HCV) infection, we characterized HCV-specific CD8 T cell lines isolated after immunomagnetic sorting of peripheral blood mononuclear cells from human leukocyte antigen A*02 (HLA-A*02) individuals with various HCV serological statuses, using recombinant HLA-A*0201 multimers loaded with three immunodominant HCV genotype 1-derived epitopes. CD8 T cells specific for these three epitopes were derived from most HLA-A*0201 individuals, regardless of their HCV serology or clinical outcome. Donors recovered from genotype 1 HCV infection were enriched for high-avidity T cells with enhanced interferon gamma (IFN-gamma), tumor necrosis factor alpha, and cytotoxic T lymphocyte responses, when compared with seronegative donors and seropositive patients infected with irrelevant HCV genotypes. Patients chronically infected with genotype 1 strain yielded almost exclusively low-avidity T cells, whose hyporesponsiveness was primarily attributable to low T cell receptor (TCR) avidity rather than intrinsic functional defects. CONCLUSION: This study suggests that strong IFN-gamma responses associated with efficient viral clearance primarily result from Ag-driven selection/survival of HCV-specific T cells expressing high-avidity TCR. It also suggests a link between the quality of the initial HCV-specific T cell repertoire and susceptibility to chronic infection.

Long-term evolution of the CAZY glycosyltransferase 6 (ABO) gene family from fishes to mammals--a birth-and-death evolution model.

Functional glycosyltransferase 6 (GT6) family members catalyze the transfer of galactose or N-acetylgalactosamine in alpha1,3 linkage to various substrates and synthesize structures related to the A and B histo-blood group antigens, the Forssman antigen, alphaGal epitope, and iGb3 glycolipid. In rat, mouse, dog, and cow genomes, we have identified three new mammalian genes (GT6m5, GT6m6, and GT6m7) encoding putative proteins belonging to the GT6 family. Among these, GT6m6 protein does not display major alterations of the GT6 motifs involved in binding of the divalent cation and the substrate. Based on protein sequence comparison, gene structure, and synteny, GT6 homologous sequences were also identified in bird, fish, and amphibian genomes. Strikingly, the number and type of GT6 genes varied widely from species to species, even within phylogenetically related groups. In human, except ABO functional alleles, all other GT6 genes are either absent or nonfunctional. Human, mouse, and cow have only one ABO gene, whereas rat and dog have several. In the chicken, the Forssman synthase-like is the single GT6 family member. Five Forssman synthase-like genes were found in zebrafish, but are absent from three other fishes (fugu, puffer fish, and medaka). Two iGb3 synthase-like genes were found in medaka, which are absent from zebrafish. Fugu, puffer fish, and medaka have an additional GT6 gene that we termed GT6m8, which is absent from all other species analyzed here. These observations indicate that individual GT6 genes have expanded and contracted by recurrent duplications and deletions during vertebrate evolution, following a birth-and-death evolution type.

Cloning of a rat gene encoding the histo-blood group B enzyme: rats have more than one Abo gene.

A genomic DNA fragment corresponding to exon 7 of the human ABO gene was amplified from rats of several inbred and outbred strains. Five different sequences were obtained, four of them corresponding to A-type sequences and one to a B-type sequence based on the amino acids equivalent to residues at positions 266 and 268 of the human enzymes. In rats from inbred strains, a single A-type sequence and the unique B-type sequence were found, whereas some animals of outbred strains presented two or three A-type sequences along with the B-type sequence. The complete coding sequence of the B-type gene was obtained; identification of the exon-intron boundaries, determined by comparison with rat genomic sequences from data banks, revealed that the rat B-type gene structure is identical with that of the mouse Abo gene. Compared with the human ABO gene and the rat A gene, it lacks exon 4. Like the rat A gene (symbol: Abo), the rat B gene (symbol: Abo2) is located on chromosome 3q11-q12. It could be shown by transfection experiments that the B-type cDNA encodes an active B transferase. A transcript of the B gene was found ubiquitously, whereas the B antigen was only detected in a restricted set of tissues. These data indicate that rats have at least two distinct Abo genes, one monomorphic gene encoding a B-specific enzyme and one or more genes in some cases encoding an A-specific enzyme.

Expression of histo-blood group A antigen increases resistance to apoptosis and facilitates escape from immune control of rat colon carcinoma cells.

A and B histo-blood group antigens are present on carcinoma cells at the early stages of cancerogenesis and tend to disappear at later stages, but it is not yet clear whether they take part to the process of tumor progression. To gain some insight into this issue, we used a rat colon carcinoma experimental model. To obtain expression of the A antigen, REG cells were cotransfected with the rat A enzyme cDNA and a rat alpha1,2fucosyltransferase cDNA, either FTA or FTB, whereas PRO cells that spontaneously have alpha1,2fucosyltransferase activity were only transfected with the A enzyme cDNA. All A antigen-expressing transfected cells derived from either REG FTA, REG FTB, or PRO parental cells were more resistant to apoptosis induced by either serum deprivation or heat shock than were their respective controls. When injected to syngeneic immunocompetent rats, A enzyme-transfected PRO cells formed tumors that grew faster than those formed by mock-transfected PRO cells. However, in immunodeficient SCID mice, no difference in growth could be observed between the two types of tumors, indicating that the faster tumor growth of the A antigen-positive cells in immunocompetent animals was due to their higher ability to escape immune control and that this was associated with their higher degree of resistance to apoptosis. These results might explain the slightly augmented incidence of carcinomas observed in A and B blood group individuals compared to O individuals.

Cloning of a rat gene encoding the histo-blood group A enzyme. Tissue expression of the gene and of the A and B antigens.

The complete coding sequence of a BDIX rat gene homologous to the human ABO gene was determined. Identification of the exon-intron boundaries, obtained by comparison of the coding sequence with rat genomic sequences from data banks, revealed that the rat gene structure is identical to that of the human ABO gene. It localizes to rat chromosome 3 (q11-q12), a region homologous to human 9q34. Phylogenetic analysis of a set of sequences available for the various members of the same gene family confirmed that the rat sequence belongs to the ABO gene cluster. The cDNA was transfected in CHO cells already stably transfected with an alpha1,2fucosyltransferase in order to express H oligosaccharide acceptors. Analysis of the transfectants by flow cytometry indicated that A but not B epitopes were synthesized. Direct assay of the enzyme activity using 2' fucosyllactose as acceptor confirmed the strong UDP-GalNAc:Fucalpha1,2GalalphaGalNAc transferase (Atransferase) activity of the enzyme product and allowed detection of a small UDP-Gal:Fucalpha1,2GalalphaGal transferase (B transferase) activity. The presence of the mRNA and of the A and B antigens was searched in various BDIX rat tissues. There was a general good concordance between the presence of the mRNA and that of the A antigen. Tissue distributions of the A and B antigens in the homozygous BDIX rat strain were largely different, indicating that these antigens cannot be synthesized by alleles of the same gene in this rat inbred strain.

Norwalk virus binds to histo-blood group antigens present on gastroduodenal epithelial cells of secretor individuals.

BACKGROUND & AIMS: Norwalk Virus (NV) is a member of the Caliciviridae family, which causes acute epidemic gastroenteritis in humans of all ages and its cellular receptors have not yet been characterized. Another calicivirus, Rabbit Hemorrhagic Disease Virus, attaches to H type 2 histo-blood group oligosaccharide present on rabbit epithelial cells. Our aim was to test if, by analogy, recombinant NV-like particles (rNV VLPs) use carbohydrates present on human gastroduodenal epithelial cells as ligands. METHODS: Attachment of rNV VLPs was tested on tissue sections of the gastroduodenal junction and on saliva from individuals of known ABO, Lewis, and secretor phenotypes. It was also tested on human Caco-2 cells and on animal cell lines transfected with glycosyltransferases complementary DNA (cDNA). Competition experiments were performed with synthetic oligosaccharides and anticarbohydrate antibodies. Internalization was monitored by confocal microscopy. RESULTS: Attachment of rNV VLPs to surface epithelial cells of the gastroduodenal junction as well as to saliva was detected, yet only from secretor donors. It was abolished by alpha1,2fucosidase treatment, and by competition with the H types 1 and 3 trisaccharides or with anti-H type 1 and anti-H types (3/4) antibodies. Transfection of CHO and TS/A cells with an alpha1,2fucosyltransferase cDNA allowed attachment of VLPs. These transfectants as well as differentiated Caco-2 cells expressing H type 1 structures internalized the bound particles. CONCLUSIONS: rNV VLPs use H type 1 and/or H types (3/4) as ligands on gastroduodenal epithelial cells of secretor individuals.