Showing papers on "Typing published in 1976"

Characterisation of human cell lines and differentiation from HeLa by enzyme typing

Abstract: THE value of a great deal of research on cells in culture depends on the certain identity of the cells under investigation. Contamination of one cell line with another, leading to mixed cultures or in some cases complete overgrowth of the original cells by the contaminating line, is a longstanding problem. Interspecific contamination has been recognised by both immunological and karyological techniques1,2, but the most striking demonstration of intra-specific contamination was by Gartler3. He presented evidence, based on the detection of common genetically determined variation in two enzymes, that many permanent tumour cell lines, set up originally in several different laboratories, were in fact HeLa cells. Recently the problem of contamination with HeLa has become a focus of general interest and there has been a search for certain chromosomal and other characteristics of HeLa in a large number of established lines4–6. There is no guarantee, however, that the contaminating cell line will always be HeLa and there appears to be a need for a quick and reliable method for the absolute identification of all human cell lines.

Bacteriocin (klebocin) sensitivity typing of klebsiella.

Abstract: High-titer preparations of Klebsiella bacteriocins (klebocins) were obtained by using mitomycin to induce standard strains of Klebsiella. Of 296 clinical isolates of Klebsiella, 67% could be typed on the basis of their sensitivity to klebocins. The method proposed in this paper affords a standard basis for the further development of klebocin typing as a suitable procedure for hospital laboratories concerned with epidemiological investigations of hospital-associated infections. Evidence is also provided to show that high-titered klebocin typing can be used in conjunction with biochemical typing to provide a sensitive epidemiological marker for Klebsiella.

Phage typing of Staphylococcus epidermidis.

Abstract: Thirteen phages were isolated from lysogenic cultures of Staphylococcus epidermidis from a clinical laboratory and used to type 223 clinical isolates of this organism. The 18 phages isolated in The Netherlands were used to type these same cultures. No correlation was observed between phage type, biotype, or clinical source of isolation. At phage concentrations of 100 times the routine test dilution, 35.0% of the cultures were typable with out phages and 21.5% were typable with the phages from The Netherlands. When only cultures in biotype 1 were considered, 43.3 and 24.1% of 141 cultures were typable with our phages and those from The Netherlands, respectively. The lytic reactions obtained with our phages were generally stronger and easier to read and the lytic patterns were, almost invariably, shorter. The typability of untypable cultures was increased 12.0% by incubation at 45 C prior to phage typing and 20% by heat shock (55 C for 5 min) prior to typing. Phage typing 5 subcultures of 20 typable cultures on 5 successive days showed that the lytic patterns were reproducible. The present status of phage typing S. epidermidis and the work needed to obtain a set of typing phages for epidemiological studies of infections by this organism are discussed.

Differentiation of Proteus mirabilis by bacteriophage typing and the Dienes reaction.

Abstract: A provisional typing schema based on sensitivity to 23 bacteriophages has been established for Proteus mirabilis. Seventy-three bacteriophages were isolated on strains of P. mirabilis (64), P. vulgaris (1), P. morganii (7), and P. rettgeri (1), but those isolated on P. mirabilis were the most useful in differentiating other strains of . mirabilis. From the 73 phages studied, the best 23 were chosen by computer analysis for the provisional system, which was then used to study P. mirabilis infections in a 500-bed general hospital. All patient isolates for 19 months were saved and then compared by bacteriophage typing and the Dienes reaction in a retrospective study. There was evidence for only three instances of cross-infection or -colonization during this time. Bacteriophage typing was very sensitive in differentiating strains, since 200 strains were differentiated into 113 different lysis patterns and 94% were typable. The Dienes reaction was useful at times but often gave reactions that were difficult to read or that changed when the tests were repeated. The bacteriophages described by Schmidt and Jeffries were also evaluated and proved useful in combination with ours. The value of bacteriophage typing was clearly established, and work toward a standardized schema for P. mirabilis should continue. Images

Preparation of typing antisera specific for O antigens of Pseudomonas aeruginosa.

Abstract: Results of serotyping 966 clinical isolates of Pseudomonas aeruginosa showed that 72% agglutinated specifically in one or another of the 16 typing antisera, but 28% agglutinated in two or more and often in as many as 10 antisera; this polyagglutinability correlated with a high incidence of cross-reactivity among the antisera. Absorption of each typing antiserum with either cell suspensions of five O-type strains or with a suspension of a particular polyagglutinable strain (SMC 247) abolished cross-reactivity in the typing antisera without significantly reducing titers against the homologous strains. All but four of the polyagglutinable strains agglutinated specifically in one or another absorbed antisera. The cross-reactions of unabsorbed antisera were interpreted to have been caused by antibodies directed not against specific O antigens but against thermostable specificities that remain undefined.

Reconstitution of the Somatic (O-) Antigenic Scheme for Providencia and Preparation of O-Typing Antisera

Abstract: The somatic (O-) antigens of the type strains of the providencia antigenic scheme were examined for their biochemical reactions and their O-specificities. The scheme of 62 O-antigens was reconstituted from 52 original type strains and 10 strains substituted for originals that either were biochemically atypical of the genus or showed inappropriate serological reactions. Thirty-six type strains showed no significant relations with other type strains, and antisera could be used for typing without absorption. Among 26 type strains, significant reciprocal relations were demonstrated, and each cross-reacting antigen was examined for specificity and for its distribution among the type strains. Antisera to these strains required absorption with cell suspensions of other type strains for production of specificity in O-typing. Each typing antiserum, at low dilution, was shown to agglutinate homologous, but not heterologous, cell suspensions of type strains, and this result demonstrated the required specificity for typing on the basis of the O-antigens.

Typing for MLC Determinants

Abstract: . MLC typing of random individuals can be performed using a panel of inactivated HLA-D homozygous cells. Eight different HLA-D specificities are now internationally accepted. The evaluation of the results must take into account both the general responding capacity of the cells to be typed and the general stimulating capacity of the typing cells. An evaluation based on the 75th percentile is discussed in detail and some pitfalls are mentioned. Furthermore a description is given of primed lymphocyte typing (PLT), where cells primed in ordinary MLC cultures to one HLA-D determinant have the ability to respond in an accelerated way to similar HLA-D antigens when re-exposed to such cells in secondary cultures. In our experiments, an excellent correlation is found between these two ways of MLC typing provided that the cells used for priming are well characterized (i.e. HLA-D homozygous cells). Finally, some clinical applications of MLC typing are described, especially in connection with transplantation and association between HLA and various diseases.

Use of phage F-phi WJ-1 of Mycobacterium fortuitum to discern more phage types of Mycobacterium tuberculosis.

Abstract: A total of 125 strains of Mycobacterium tuberculosis from the Southeastern area of the United States was subjected to phage typing. In addition to the five major mycobacteriophages, a new phage, F-phi WJ-1, was used in the study. The results obtained with the five major phages were: type A0, 35.2%; TYPE B, 29.6%, and type C, 4.0%. The remaining 21.2% of the strains phaged typed as subgroups A1 through A6. These percentages were similar to the typing results of earlier studies. The new phage, F-phi WJ-1, subdivided each of the phage types, with the exception of type C, into two subgroups. The possible role of host modification-restriction of the phages used in phage typing of strains of M. tuberculosis is discussed.

Serological classification and typing of Clostridium botulinum

Abstract: Serological classification of Cl. botulinum, based on the antigenic structure of the toxins produced, is distinguished by the behaviour of the toxin-antitoxin mixtures in in vivo neutralization tests. Observations on the dissimilarity between strains within types, the behaviour of antitoxins in the cross-neutralization tests, the established concepts of the antigenic structure of the toxin types and the lack of a standard methodology for typing, have led to the definition of the terms efficiency, type, subtype, intratypic serological variant (ISV), and degree of serological homology. These definitions are primarily applied to typing and to the establishment of the taxonomic serological categories of type, subtype and ISV. In the case of antitoxin standardization, the accepted standard methods must be followed.

Evidence for several closely linked genes involved in generation of proliferation in mlc.

Abstract: Eight provisional groups of HLA-D specificities (MLR stimulating determinants) have been defined during the VI International Histocompatibility Workshop 1975. Each D-specificity group was defined by two or more D-locus homozygous typing cells. Population studies with the typing cells and mutual MLR between cells belonging to the same group demonstrate some differences within each D-specificity group. In this study we present data obtained with two HLA-D homozygous typing cells representing the DW4 specificity group. Both cells were included in the workshop and were shown in population studies to belong to the DW4 group. Mutual MLR between the two cells, however, is positive. The differences in the determinants expressed by these two cells are confirmed in family-studies including parents and other family members of each typing cell donor and of families unrelated to both cell donors. The typing cells homozygous for B12,DW4 shows very low typing responses when tested against some responders heterozygous for B12 while the BW15,DW4 homozygous typing cells shows the lowest typing responses to some BW15 heterozygous responders. One family is presented where both parents express a DW4 determinant. The parents show different response pattern to the two typing cells. Independent segregation of the two different DW4 is observed in the family. This data suggests that the HLA-D region may be composed of genetic subloci. The two different DW4 specificities described in this paper may express determinants on more than one locus. These determinants could, however, occur in the population in strong positive genetic linkage disequilibrium.

Developments in histocompatibility testing.

Abstract: Recent progress in HLA typing involves new methods which allow typing for MLC (mixed lymphocyte culture) and Ia (immune associated) antigens. These antigens seem to play a major role in transplant rejection in HLA non-immunised patients. When the new typing methods eventually become applied in matching of kidneys it seems likely that the results of kidney transplantation will be significantly improved.