Typing

About: Typing is a research topic. Over the lifetime, 5010 publications have been published within this topic receiving 146539 citations.

Sequencing-based typing of HLA-B*51 alleles and the significant association of HLA-B*5101 and -B*5108 with Behçet's disease in Greek patients.

Abstract: Behcet's disease (BD) is widely known to be strongly associated with human leukocyte antigen (HLA) B51 in many different ethnic groupsRecently, HLA-B51 allele typing of Greek BD patients was performed to study the distribution of B*5101-B*5107 alleles in this Greek population, the B51 antigen strongly associated with BD was found to be predominantly encoded by allele B*5101 As it is now known that the B51 antigen can be encoded by 21 alleles, B*5101-B*5121, we performed HLA-B*51 allele genotyping among 58 Greek patients with BD After serological HLA typing, typing of HLA-B*51 alleles was performed using the polymerase chain reaction-sequencing-based typing (PCR-SBT) method The frequency of the B51 antigen was found to be significantly higher in the patient group as compared with the control group (759% of patients vs 220% of controls In the genotyping of B51 alleles, 34 out of 44 B51-positive patients possessed B*5101, 13 out of the 44 carried B*5108 In contrast, all of the 9 B51-positive normal controls carried B*5101 This study revealed a strong association between Greeks with BD, both B*5101, B*5108, provided important insights into the molecular mechanism underlying the association between HLA status, this disease

Comparison of molecular and immunological typing of isolates of Rice yellow mottle virus.

Abstract: Isolates of Rice yellow mottle virus (RYMV) were typed at the molecular level through the sequences of the open reading frame (ORF) 4 (coding for the coat protein) and ORF1 (coding for the movement protein), and serologically by means of polyclonal and monoclonal antibodies The overall patterns of diversity shown by molecular and serological analyses were similar: East-African isolates differed from West-African ones, and the West-African isolates from forest differed from the savannah ones Each major strain had a different serological profile However, molecular typing was more discriminating than immunological typing since several sequence variants belonged to the same serotype In rare instances, there were explainable discrepancies between molecular and serological typing Two amino acids at positions 115 (alanine vs threonine) and 191 (valine vs threonine) consistently discriminated between the major serotypes These positions were located in antigenic sites as revealed by Spot-scan method and were recognised by discriminating monoclonal antibodies One shared epitope, lying within a conserved region, may be responsible for the cross-reactivity between RYMV isolates A rationale for the correlation between molecular and immunological typing of RYMV and other sobemoviruses is proposed

Positive correlation between oligonucleotide typing and T-cell recognition of HLA-DP molecules.

Abstract: The identification of 19 different HLA-DPB1 sequences implicates the existence of more DP specificities than can be typed for with cellular methods. How many of the DP beta sequences can be specifically recognized by T cells, and which of the polymorphic regions can contribute to the specificity of allorecognition, is not known. In order to investigate the distribution and the immunological relevance of recently described DPB1 alleles, we have typed a panel of 98 randomly selected Dutch Caucasoid donors for the HLA-DPB1 locus by oligonucleotide typing. Comparison of the typing results with primed lymphocyte typing (PLT) defined DP specificities shows an extremely good correlation. Moreover, additional alleles could be defined by oligonucleotide typing reducing the number of DP blanks in the panel. By selecting the appropriate responder stimulator combinations we were able to show that distinctive PLT reagents against oligonucleotide defined specificities DPB1*0401, DPB1*0402, DPB1*0901, and DPB1*1301 can be generated. To investigate in more detail which part of the DP molecule is responsible for the specificity of T-cell recognition, T-cell clones were generated against HLA-DPw3. The clones were tested for the recognition of stimulators carrying DPB1 alleles which had been defined by oligonucleotide typing and sequence analyses and which differed in a variable degree from DPB1*0301. The recognition patterns demonstrated that differences of one amino acid in polymorphic regions situated either in the beta sheets or alpha helix of the hypothetical model of the HLA class II molecule can eliminate T-cell recognition. Furthermore, sequence analyses revealed a new DPB1 allele designated DPB1*Oos.

The current MLVA typing scheme for Enterococcus faecium is less discriminatory than MLST and PFGE for epidemic-virulent, hospital-adapted clonal types.

Abstract: Background MLVA (multiple-locus variable-number tandem repeat analysis) is a reliable typing technique introduced recently to differentiate also isolates of Enterococcus faecium. We used the established VNTR (variable number of tandem repeats) scheme to test its suitability to differentiate 58 E. faecium isolates representing mainly outbreaks and clusters of infections and colonizations among patients from 31 German hospitals. All isolates were vancomycin-resistant (vanA type). Typing results for MLVA are compared with results of macrorestriction analysis in PFGE (pulsed-field gel electrophoresis) and MLST (multi-locus sequence typing).

Typing of Proteus strains by proticine production and sensitivity.

Abstract: SUMMARY A simple, reliable and highly discriminating scheme for the bacteriocine typing of Proteus has been developed. Strains are typed on MacConkey's agar according to their ability to produce a proticine active against one of 14 indicator strains having a single and specific proticine sensitivity and also according to their sensitivity to the different proticines of 13 proticine-producing strains. This new scheme of combined production and sensitivity typing was formulated after 250 strains of Proteus from clinical material had been examined for the production of proticines active against the 24 indicator strains of Cradock-Watson's proticine typing scheme and for proticine activity and sensitivity towards each other. Three new types of proticinogenic strains were discovered and defined. Strains producing proticines of types 1, 2 and 3 were isolated frequently. These common proticines could be subtyped by their different actions on newly characterised indicator strains. By means of this production/sensitivity (P/S) typing scheme, 250 Proteus strains were differentiated into 90 distinct types, whereas typing by sensitivity alone distinguished only 40 types and typing by production alone distinguished only 20 types (including subtypes).