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PubMed1990

Serotype-related antigen of Trichosporon cutaneum in the induction of summer-type hypersensitivity pneumonitis: correlation between serotype of inhalation challenge-positive antigen and that of the isolates from patients' homes.

Inhalation challenge with the culture filtrate-antigens prepared from two strains of different serotype of Trichosporon cutaneum (TIMM 1573, serotype I; TIMM 1318, serotype II) was performed on patients with summer-type hypersensitivity pneumonitis and asymptomatic seropositive family members. Of the 17 patients, 12 were strongly positive, four were mildly so, and one was negative. Interestingly, of the 16 inhalation challenge-positive patients, four reacted to both serotypes I and II, five to serotype I only, and seven to serotype II only. There was a good correlation between the serotype inhalation challenge-positive antigen and that of T. cutaneum isolated from the homes of two patients' homes. A strain of T. cutaneum demonstrating a new serotype was isolated from the homes of two patients, one of whom was negative to both serotypes I and II. Specific antibody activity, lymphocyte proliferative response, and skin reaction to the antigens were also positive, but these findings were not useful to discriminate the inhalation challenge-positive from the inhalation challenge-negative antigen. Neither of the two asymptomatic family members responded. These results indicate that inhalation challenge in patients with summer-type hypersensitivity pneumonitis is provoked by the serotype-related antigen of T. cutaneum, reflecting the sensitization of these patients in their homes.

Alveolitis, Extrinsic Allergic↗
PubMed1988

Serologic studies of Actinobacillus (Haemophilus) pleuropneumoniae strains of serotype-3 and their antigenic relationships with other A pleuropneumoniae serotypes in swine.

Serotype-3 strains of Actinobacillus (Haemophilus) pleuropneumoniae possess epitopes shared with almost all other Actinobacillus serotypes. Common epitopes detected in particulate antigens were heat-labile and heat-stable and were of minor nature. Additional cross-reactive epitopes were detected in soluble and particulate antigens prepared from strains of serotypes 3, 6, and 8. Cross-reactions occurring between serotype-3 antigens and those of other serotypes were of 2 types: one associated mainly with 2-mercaptoethanol (2-ME)-sensitive IgM antibodies and the other associated mainly with 2-ME-resistant IgG antibodies. The cross-reactivity between serotypes 3, 6, and 8 was associated mainly with IgG antibodies, as shown by the results of 2-ME tube agglutination, 2-ME-indirect hemagglutination, and coagglutination tests. None of the tests was entirely satisfactory for serotyping serotype-3 isolates, mainly as a result of overlapping of type-specific antigenic determinants of serotypes 3, 6, and 8 in different combinations in the same strain. A combination of tests, using particulate and soluble antigens, may be necessary for typing of serotype-3 isolates.

Actinobacillosis↗
PubMed2003

Why are dengue virus serotypes so distantly related? Enhancement and limiting serotype similarity between dengue virus strains.

Dengue virus, the causative agent of dengue fever, has four major serotypes characterized by large genetic and immunological distances. We propose that the unusually large distances between the serotypes can be explained in the light of a process of antibody-dependent enhancement (ADE) leading to increased mortality. Antibody-dependent enhancement results from a new infection with a particular serotype in an individual with acquired immunity to a different serotype. Classical dengue fever causes negligible mortality, but ADE leads to the risk of developing the significantly more dangerous dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS). A mathematical model is presented that describes the epidemiological dynamics of two serotypes of a pathogen where there is the possibility of co-infection and reinfection by a different serotype, along with increased mortality as a result of enhancement. We show that if there is no or slightly increased mortality after reinfection (enhancement), serotypes with a small immunological distance can stably coexist. This suggests that a cloud of serotypes with minor serological differences will constitute the viral population. By contrast, if enhancement is sufficiently great, a substantial immunological distance is necessary for two serotypes to stably coexist in the population. Therefore, high mortality owing to enhancement leads to an evolutionarily stable viral community comprising a set of distantly separated serotypes.

Antibody-Dependent Enhancement↗
PubMed1997

Single point mutations may affect the serotype reactivity of serotype G11 porcine rotavirus strains: a widening spectrum?

A panel of single and double neutralization-resistant escape mutants of serotype G11 porcine rotavirus strains A253 and YM, selected with G11 monotype- and serotype-specific neutralizing monoclonal antibodies (MAbs) to VP7, was tested in neutralization assays with hyperimmune sera raised against rotavirus strains of different serotypes. Escape mutants with an amino acid substitution in antigenic region A (amino acids [aa] 87 to 101) resulting in a residue identical or chemically similar to those present at the same positions in serotype G3 strains, at positions 87 for strain A253 and 96 for strain YM, were significantly more sensitive than the parental strains to neutralization with sera against some serotype G3 strains. Also, one YM antigenic variant (YM-5E6.1) acquired reactivity by enzyme-linked immunosorbent assay with MAbs 159, 57/8, and YO-1E2, which react with G3 strains, but not with the serotype G11 parental strain YM. Cross-adsorption studies suggested that the observed cross-neutralization by the G3-specific sera was due to the sera containing antibodies reactive with the parental strain plus antibodies reactive with the epitope(s) on the antigenic variant that mimick the serotype G3 specific one(s). Moreover, antibodies reactive with antigenic region F (aa 235 to 242) of VP7 might also be involved since cross-reactivity to serotype G3 was decreased in double mutants carrying an additional mutation, which creates a potential glycosylation site at position 238. Thus, single point mutations can affect the serotype reactivity of G11 porcine rotavirus strains with both monoclonal and polyclonal antibodies and may explain the origin of rotavirus strains with dual serotype specificity based on sequence divergence of VP7.

Amino Acid Sequence↗
PubMed1994

[Immunological cross-reaction of serotype I Marek's disease virus 38kD phosphorylated protein with serotype II and III viruses].

Marek's disease virus (MDV) 38kD phosphorylated protein (pp38), which was identified by monoclonal antibody (mAb) H19 specific to pathogenic serotype I of MDV, has been recognized as a transformation-associated antigen specific to serotype I of MDV. The recombinant pp38 was prepared and purified from pp38-expressing recombinant baculovirus infected Sf9 cell lysates through a mAb H19-affinity column. In indirect fluorescence antibody test, the mouse sera against the purified recombinant pp38 not only gave a high titer to serotype I strain GA-infected CEF but also gave a reasonable titers to serotype II strain Z4- and serotype III HVT strain Fc126-infected CEF. In another way, the pp38- expressing recombinant baculovirus infected Sf9 cells reacted with anti-serotype I MDV chicken sera as well as with anti-serotype II and serotype III MDV chicken sera respectively. The results imply that both serotypes II and III of MDV probably contain a homologue to pp38 of serotype I.

Antigens, Viral↗
PubMed1992

Serotype specificity of immunological assays for the capsular polymer of Actinobacillus pleuropneumoniae serotypes 1 and 9.

The cross-reactivity of the purified polysaccharides of Actinobacillus pleuropneumoniae serotypes 1 and 9 were examined using a variety of highly sensitive assays, such as radioimmunoassay, latex agglutination, enzyme-linked immunosorbent assay (ELISA), and immunoblotting. In addition, conventional immunodiffusion was included for comparison. Latex agglutination, utilizing affinity-purified IgG to capsule, was also used to serotype whole cells. Agglutination or precipitation tests (radioimmunoassay, latex agglutination, and immunodiffusion) indicated no cross-reactivity between the capsules of serotypes 1 and 9, and no cross-reactivity between whole cells by latex agglutination. Assays that required binding of the capsule to a solid support (ELISA and immunoblotting) did demonstrate cross-reactions between serotypes 1 and 9 capsules, although reactions with the heterologous serotype were weaker than with the homologous serotype. The cross-reactivity could not be attributed solely to nonspecific factors because similar cross-reactivity did not occur with serotype 5 or 7 capsules by any assay. Reactivity of antisera with homologous or heterologous capsule was reduced, but not completely eliminated, by adsorption with washed, live bacteria of the heterologous serotype. Thus, the assay, as well as the antigen or specificity of the antibody reagent used, may influence the results of A. pleuropneumoniae serotyping or serological tests.

Actinobacillus pleuropneumoniae↗
PubMed1998

Serotype 19A variants of the Spanish serotype 23F multiresistant clone of Streptococcus pneumoniae.

Multiply-antibiotic-resistant isolates of serogroup 19 Streptococcus pneumoniae, possessing altered penicillin-binding protein (PBP) 1A, 2B, and 2X genes that are indistinguishable from those of the Spanish multiresistant serogroup 23F clone, are now commonly encountered in Spain. Those isolates that have been serotyped express type 19F capsular polysaccharide. Serotyping of further isolates, and hybridization using a serotype 19F-specific probe, has shown that some of them are serotype 19A, rather than 19F. The Spanish multiresistant serotype 19A, 19F, and 23F multiresistant strains were all shown to be very closely related in overall genotype, as they were indistinguishable by REP-PCR and by the sequencing of internal fragments of three house-keeping genes. The serotype 19A multiresistant strains, like the serotype 19F multiresistant strains, therefore appear to be a serotype variant of the Spanish multiresistant serotype 23F clone, which presumably has arisen by recombination at the capsular locus.

Bacterial Capsules↗
PubMed1986

Correlation of serotype specificity and protein structure of the five U.S. serotypes of bluetongue virus.

The relationship between serotype specificity and protein structure was studied by polyacrylamide gel electrophoresis, peptide mapping and radioimmune precipitation (RIP) of structural and non-structural proteins of the five U.S. serotypes of bluetongue virus (BTV). The surface proteins, VP2 and VP5, showed the most variation in size among the serotypes. Peptide mapping of the proteins showed that VP2 is unique for each of the U.S. serotypes. The nucleocapsid and non-structural proteins showed a high degree of conservation, whereas the other surface protein, VP5, showed intermediate conservation among the serotypes. Monospecific neutralizing antiserum produced in rabbits against each serotype was used in cross-RIP against cytoplasmic extracts prepared from cells infected with each BTV serotype. There were extensive cross-reactions among those proteins which showed a high degree of structural conservation, whereas VP2 was immunoprecipitated best in the homologous RIP system. Thus, a correlation between serotype specificity and protein structure was shown among the five U.S. serotypes of BTV.

Antigens, Viral↗
PubMed1997

Divergent activity and function of superoxide dismutases in Pasteurella haemolytica serotypes A1 and A2 and Pasteurella trehalosi serotype T10.

Representative strains of Pasteurella haemolytica serotypes A1 and A2 and Pasteurella trehalosi serotype T10 were examined for the presence of superoxide dismutase. Visualisation of superoxide dismutase enzyme activity on polyacrylamide gels, and specific inhibition with potassium cyanide verified a copper/zinc (Cu/Zn) superoxide dismutase only in serotype A2 whereas serotypes A1 and T10 showed other superoxide dismutase activity. Using a simple freeze-thaw method the cellular location of superoxide dismutase enzyme activity was determined in all three serotypes. In serotypes A1 and A2 but not T10 superoxide dismutases were located in the periplasm. The viability of serotypes A2 and T10 cells in the presence of exogenous superoxide was unchanged over a 30 min period, whereas serotype A1 cells declined in viability between 15 and 30 min. Purified immunoglobulin from sheep convalescent serum did not reduce superoxide dismutase activity in the serotypes in an in vitro assay. The presence of this enzyme within the pasteurellae suggests a supportive role in the virulence of this major pathogen of ruminants.

Animals↗
PubMed1989

Reactivity of VP4-specific monoclonal antibodies to a serotype 4 porcine rotavirus with distinct serotypes of human (symptomatic and asymptomatic) and animal rotaviruses.

Thirteen hybridomas secreting VP4-specific monoclonal antibodies against the Gottfried strain of porcine rotavirus (serotype 4) were produced and characterized. Nine of the hybridomas secreted neutralizing monoclonal antibodies (N-MAbs) against Gottfried rotavirus. These N-MAbs were divided into five distinct groups (groups I to V) according to their patterns of reactivity with different serotypes of human and animal rotaviruses. Group I N-MAbs (n = 3) were cross-reactive with five different serotypes of human rotavirus examined by a plaque reduction virus neutralization test. Group II N-MAbs (n = 3) neutralized all symptomatic human rotavirus serotypes tested and asymptomatic human rotavirus serotype 4 to a low titer. The single group III N-MAb neutralized mainly symptomatic human rotavirus serotypes 2 and 9 and none of the asymptomatic human rotavirus serotypes. The one N-MAb in group IV reacted at low titers with only asymptomatic human rotavirus serotypes 1 through 4. A group V N-MAb recognized serotype 4 porcine rotaviruses (Gottfried and SB-2) but no other human or animal rotaviruses examined. None of the N-MAbs recognized any animal rotaviruses tested (SA-11, RRV, OSU, NCDV, and B223), except for the Gottfried and SB-2 rotaviruses. The failure of N-MAbs (groups I to IV) to react with any animal rotaviruses tested but their ability to react variably with all human rotaviruses tested suggest that neutralizing epitopes on the VP4 protein are highly conserved between the Gottfried porcine and human rotaviruses. The Gottfried rotavirus may possibly represent a naturally occurring reassortant between pig and human rotaviruses or a rotavirus which is human in origin but pathogenic for swine.

Animals↗
PubMed1991

Serotyping of Canadian isolates of Treponema hyodysenteriae and description of two new serotypes.

A total of 30 isolates of Treponema hyodysenteriae collected in the Saint-Hyacinthe (Quebec, Canada) area were serotyped by agar gel double immunodiffusion by using extracted lipopolysaccharide and hyperimmune rabbit antisera. Only 17% (5 of 30) of the isolates were typed with antisera specific for each of the seven known serotypes of T. hyodysenteriae. Antisera raised against 11 untypeable local isolates were then produced and tested against each lipopolysaccharide extract. Results showed two serologically distinct groups among 21 of the 25 untypeable isolates. The isolates in each group shared identical antigens. No detectable reactions could be observed between antisera raised against these 11 isolates and the antigens extracted from 7 reference serotype strains. On the basis of these results, two new serotypes of T. hyodysenteriae, serotypes 8 and 9, are proposed. We also propose isolate FM 88-90 as the reference strain for serotype 8 and isolate FMV 89-3323 as the reference strain for serotype 9. These two new serotypes, which represented 70% of the isolates tested, seem to be the major serotypes found in the province of Quebec.

Animals↗
PubMed1993

Two-way cross-neutralization mediated by a shared P (VP4) serotype between bovine rotavirus strains with distinct G (VP7) serotypes.

Among bovine rotavirus strains, there are three G serotypes (G6, G8, and G10) and three P (VP4) serotypes (PB1, PB2, and PB3, which are defined on the basis of strains NCDV, UK, and B223, respectively). Plaque reduction neutralization assays with hyperimmune antisera disclosed two-way antigenic relationships of strain KN-4 with strain KK-3 (G10, PB3) as well as with strains NCDV (G6, PB1) and 0510 (G6, PB2). Neutralization assays with monoclonal antibodies specific for G6, G10, and PB3 revealed that KK-3 and KN-4 had the same P serotype (PB3) but that neither G6- nor G10-specific monoclonal antibody neutralized KN-4. Comparison of the VP7 gene sequence of KN-4 with those of other bovine rotavirus strains indicated that KN-4 was more similar to G6 bovine strains than to KK-3 and other G10 strains, suggesting that the G serotype of KN-4 was G6. From these results, we concluded that the two-way cross-neutralization between KN-4 and NCDV or 0510 was mediated by shared G6 serotype specificity, whereas the two-way cross-neutralization between KN-4 and KK-3 was mediated by shared P serotype specificity (PB3). Thus, KN-4 and KK-3 represent the first reported example of a two-way antigenic relationship mediated only by the P serotype. This article emphasizes the need for adopting a binary serotyping system and development of reagents which will enable classification of rotaviruses based on their G and P serotype specificities.

Amino Acid Sequence↗
PubMed1982

Serotypes of red clover necrotic mosaic virus. I. Characterization of three serotypes.

Three serotypes (A, B and C) were distinguished based on serological differences between isolates of red clover necrotic mosaic virus (RCNMV). Isolate TpM34, representative of serotype A, induced the formation of antibody only against homologous antigen. By contrast, isolate TpM48, representative of serotype B, induced the formation of 3 groups of antibody; the group of type-specific antibody was present in a higher titre than the other two antibody groups. Isolate 63/70, representing serotype C, also induced the production of type-specific antibody in a higher titre as compared with antibodies reacting with type A and B antigens. The distinct behaviour of the 3 serotypes was also manifested on immunoelectrophoresis in agarose gel. In anionic barbital buffer, serotypes A and C showed a higher mobility than representatives of serotype B, but in cationic environment serotype A showed a higher mobility than serotypes B and C.

Antigens, Viral↗
PubMed1989

Sequence analysis of the gene encoding the serotype-specific glycoprotein (VP7) of two new human rotavirus serotypes.

Human rotavirus strains 69M and WI61 are distinct from human rotavirus serotypes 1, 2, 3, and 4 and from each other by plaque reduction neutralization and have been proposed as new human rotavirus serotypes (serotype 8 and serotype 9, respectively). The nucleotide sequence of the gene encoding the serotype-specific capsid glycoprotein, VP7, of strains 69M and WI61 was determined. In addition, the sequence of the VP7 gene of strain F45 (serotypically indistinguishable from WI61) was determined. Comparative analyses of the nucleotide and deduced amino acid sequences with those of reference strains from serotypes 1,2,3,4,5, and 6 demonstrated that WI61 and F45 share a high degree of sequence similarity with each other and that strains 69M, WI61, and F45 are distinct from established serotypes 1,2,3,4,5, and 6 in nine defined regions of the VP7 which are variable across rotavirus serotypes.

Amino Acid Sequence↗
PubMed2002

Prevalence of, and antigenic variation in, serotype G10 rotaviruses and detection of serotype G3 strains in diarrheic calves: implications for the origin of G10P11 or P11 type reassortant asymptomatic strains in newborn children in India.

Previous studies have shown predominant association of G10P11 type bovine rotavirus-derived reassortant strains with asymptomatic infections in newborn children in India. To understand the epidemiological and genetic basis for the origin of these strains in humans, the relative frequencies of different serotypes among bovine rotaviruses (BRVs) isolated from southern, western and central regions of the country were determined by subgroup and serotype analysis as well as nucleotide (nt) sequence analysis of the genes encoding the outer capsid proteins VP4 and VP7. Since the human G10P11 asymptomatic neonatal strain I321 possessed NSP1 from a human rotavirus, to determine its genetic origin in the bovine strains, comparative analysis of partial gene sequences from representative G10P11 strains was also carried out. The following observations were of great epidemiological significance, (i) G10P11 strains predominated in all the three regions with frequencies ranging between 55.6% and 85.2%. In contrast to the high prevalence of G6 strains in other countries, only one G6 strain was detected in this study and G8 strains represented 5.8% of the isolates, (ii) among the G10 strains, in serotyping ELISA, four patterns of reactivity were observed that appeared to correlate with the differences in electropherotypic patterns and amino acid (aa) sequence of the VP7, (iii) surprisingly, strains belonging to serotype G3 were detected more frequently (10.7%) than those of serotypes G6 and G8 combined, while strains representing the new serotype (G15) were observed in a single farm in Bangalore, and (iv) about 3.9% of the isolates were nontypeable as they exhibited high cross-reactivity to the serotyping MAbs used in the study. Comparative analysis of the VP7 gene sequence from the prototype G3 MAb-reactive bovine strain J63 revealed greatest sequence relatedness (87.6% nt and 96.0% aa) with that of serotype G3 rhesus-monkey strain RRV. It also exhibited high sequence homology with the VP7 from several animal and animal rotavirus-related human G3 strains (Simian SA11; equine ERV316 and FI-14; canine CU-1 and K9; porcine 4F; Feline Cat2 and human HCR3, YO and AU1). Partial nucleotide sequence analysis of the NSP1 gene of J63 showed greatest nt sequence homology (95.9%) to the NSP1 gene allele of the Indian G8 strain, isolated from a diarrheic child, which is likely to have been transmitted directly from cattle and 92.6% homology to that of the bovine G8 strain A5-10 suggesting the likely origin of J63 by gene reassortment between a bovine G8 strain and a G3 animal strain. Prevalence of G10P11 strains in cattle and G10P11 or P11 type reassortant strains in asymptomatic neonates as well as detection of G8P[1] strains in diarrheic children support our hypothesis for bidirectional transmission of rotaviruses between humans and cattle and origin of novel strains catalyzed by the age-old traditions and socio-economic conditions in India.

Amino Acid Sequence↗
PubMed1972

Classification of Neisseria meningitidis group B into distinct serotypes. IV. Preliminary chemical studies on the nature of the serotype antigen.

Group B Neisseria meningitidis has been subdivided into 11 distinct serotypes by a sensitive bactericidal inhibition technique. The antigens responsible for induction of bactericidal type-specific antibodies were found to be extractable from the group B cells with heating at 100 C either by 0.017 n HCl in saline or by normal saline. These extracted serotype antigens were detected by a capillary precipitin test. The development of methods for extraction and assay of the serotype antigens permitted studies on their immunochemistry. The serotype antigens were distinct from the group-specific substance. Acid extracts contained abundant serotype antigen, but were devoid of group-specific substance. The identity of serotype antigens as proteins was confirmed by their sensitivity to Pronase and trypsin. The molecular weight of these antigens as estimated by G-200 Sephadex chromatography and by electrophoresis in polyacrylamide gels is in excess of 200,000 daltons. Saline extracts containing the serotype antigen could be fractionated into three distinct fractions with acetic acid: pH 4.5 and pH 3.5 precipitated fractions and a pH 3.5 supernatant fraction. The pH 4.5 precipitated fraction contained the serotype antigen.

Acetates↗