Reciprocal Tests Research Articles

New human adenovirus (candidate adenovirus type 35) causing fatal disseminated infection in a renal transplant recipient.

An antigenically distinct adenovirus is described which was isolated in March 1973 from the lungs and kidney of a 61-year-old woman who died of diffuse interstitial adenovirus pneumonia 55 days after receiving a cadaveric renal allograft. Complement fixation, hemagglutination inhibition, and serum neutralization tests on sequential serum specimens from the patient confirmed that the adenovirus infection occurred in coincidence with her clinical illness and failed to document concomitant infection by any other common respiratory agent. Pathological and virological findings indicated that the pneumonia was only one manifestation of a disseminated adenovirus infection, the source of which may have been a latent infection pre-existing in the donor kidney. The adenovirus, purified by terminal dilution and plaque procedures, has antigenic, morphological, biological, biophysical, host susceptibility, and hemagglutinating properties characteristic of adenovirus group 1A. Buoyant densities in CsCl are 1.340 g/ml for the virion, 1,300 g/ml for the group complement-fixing (hexon) antigen, and 1.290 g/ml for the major soluble complete hemagglutinin (dodecon). The virus was serologically distinct from adenoviruses 1 to 34 in reciprocal serum neutralization tests with antisera to these viruses. We propose this virus as candidate adenovirus type 35 (holden).

ANALYSIS OF THE BINDING SITES OF PHYTOHEMAGGLUTININS AND PEMPHIGUS ANTIBODY IN THE INTERCELLULAR AREAS OF THE EPIDERMIS

ABSTRACTIn order to characterize the pemphigus antigen(s), the binding sites of phytohemagglutinins and pemphigus antibody were studied by the combined use of fluorescein‐labelled Concanavalin A (Con A‐FITC), Phytohemagglutinin‐P‐FITC (PHA‐P‐FITC) and pemphigus antibody. Reciprocal blocking test of PHA‐P and pemphigus antibody revealed that the binding sites of PHA‐P and pemphigus antibody were independent, whereas those of Con A and pemphigus antibody were very closely related though not identical. Pemphigus skin with deposition of IgG or with presumable saturation of the binding sites with high‐titred antibody showed capability to Con A binding. Treatment of normal skin sections with Hyaluronidase or Neuraminidase did not supply any clue to the histochemical analysis of pemphigus antigen(s), since the binding sites of pemphigus antibody were destroyed in the buffer, prior to the enzyme digestion. These results suggested that the binding sites of pemphigus antibody in the intercellular areas consist, at least, of carbohydrates or glycoproteins that contain alpha‐methyl‐D‐mannoside or alpha‐methyl‐D‐glucoside.

A loop-structure in the serological classification system of tymoviruses

Abstract Two newly described tymoviruses, Kennedia yellow mottle (KYMV) and Clitoria yellow vein viruses, can be fitted into the serological classification scheme which we recently proposed if it is extended to contain a loop-structure. KYMV forms a link between turnip yellow mosaic virus (TYMV) and some other viruses which are only distantly related to TYMV. Plantago mottle virus is closely related to Scrophularia mottle and ononis yellow mosaic viruses. Our present knowledge on the serological interrelationships in the tymovirus group is summarized in a classification scheme in which the average serological differentiation indices of reciprocal tests are depicted as length units.

Serological studies and isolations of serotype hardjo and Leptospira biflexa strains from horses of Argentina.

Three pathogenic leptosipras and 12 saprophytic Leptospira biflexa strains were isolated from 72 apparently normal horse kidneys collected at an abattoir in Argentina. Cross-agglutination reaction patterns of the pathogens showed that they were antigenically homologous with members of the Hebdomadis group. When one of the strains was compared to Hebdomadis serotypes in reciprocal agglutination-absorption tests, it was found to be serologically homologous to serotype hardjo. This is the first known report of an isolation of this serotype from horses. Serological tests were also carried out on randomly collected abattoir sera from 245 horses to determine the prevalence of equine leptospirosis. Significant antibody titers (1:100 or greater) were found in 74.6% of the sera. Predominant reactions occurred with the antigens pomona, hebdomadis group, pyrogenes, tarassovi, and canicola. Agglutination tests performed with antigen prepared with one of the saprophytic biflexa isolates showed seropositive reactions in 99.1% of the equine sera, with agglutination titers ranging from 1:100 to 1:3,200. Absorption of selected horse sera with the saprophytic strain removed the agglutinins to Leptospira interrogans serotypes. This suggests the possibility that L. biflexa strains may act as an antigenic stimulus and account for some of the persistent multiple cross-reaction patterns of equine sera with pathogenic serotypes.

Symbiote-free hemoflagellates, Blastocrithidia culicis and Crithidia oncopelti: their liver factor requirement and serologic identity.

Several aposymbiotic strains of Blastocrithidia culicis and Crithidia oncopelti were cultivated in Trager's chemically defined medium as well as in a blood broth, both supplemented with 0.25% (v/v) liver extract concentrate. For all such strains, the liver extract was found to serve as an essential growth factor in the defined medium and as growth promoting additive in the blood broth. The active molecules were found to be water-soluble, heat stable, dialyzable, and probably nonlipid fractions. Antisera were developed in rabbit against all the available aposymbiotic strains. An almost total cross-reactivity at very high titers was observed in reciprocal agglutination test using strains with and without the bacterial symbiotes. These results indicate that the loss of the symbiotes does not affect the antigenic identity of B. culicis and C. oncopelti.

Salt permeation through an ionic membrane and a test of onsager reciprocity

The salt permeation fluxes through a cation exchange membrane have been measured for NaBr, CsBr and SrBr2 as functions of concentration. The data were obtained from determinations of forward and back fluxes by using radio-tracers.

The kinetics of the thermofluctuation-Induced micro- and macrocrack growth in plastic metals

The growth rate of main cracks at different temperatures and under the static load has been investigated in aluminum and zinc foils. The observation of the crack growth during loading has been made by means of general microfilming as well as by electron microscope. It has been shown that the growth of main cracks occurs by means of the initiation, development, and coalescence of secondary microcracks which arise at the tip of the main one. The interaction and the growth of cracks of all dimensions, from submicroscopic and up to macroscopic, takes place at constant rate, without any steps. The rate depends exponentially upon the applied stress and the reciprocal test temperature; the activation energy of the crack growth process is near to that of sublimation for the metals.

Serotyping of Avian Infectious Bronchitis Viruses by the Virus-Neutralization Test

The antigenic relationships of 12 strains of infectious bronchitis virus (IBV) were evaluated by a virus-neutralization procedure similar to that used in typing human rhinoviruses. Such a procedure consists of reciprocal neutralization tests performed by reacting 32-320 EID50 or plaque-forming units of virus with 20 antibody units of antiserum. Eight serologic groups were identified by chicken embryo assay, and 4 by plaque-reduction (90%). In general, serologic groupings were not distinct but reflected numerous intergroup relationships. The contrasting results exhibited by indicator systems are viewed as differences in the accuracy of the methods employed. It is suggested that before an IBV classification scheme can be proposed, agreement must be reached on the most suitable indicator system, techniques must be standardized, and reference viruses and antisera distributed to several institutions for comparison testing. In addition, cross-protection studies are needed to determine the importance of IBV serotypes and/or variants on vaccine efficacy.

Serological and pathogenicity studies with some unclassified porcine adenoviruses

Eight unclassified porcine adenoviruses were compared serologically with each other and with prototype strains of porcine adenovirus types 1 to 4 by means of reciprocal virus neutralization tests. There was no relationship between any of the unclassified viruses and porcine adenovirus type 4, but unidirectional cross reactions did occur between 7 of the new viruses and one or other of porcine adenovirus types 1 to 3. In addition, cross reactions occurred among all the unclassified viruses, but all were unidirectional. Each of the unclassified viruses was inoculated intranasally into 2 hysterotomy-derived, colostrum-deprived, 7-days-old piglets. One piglet of each pair was killed 6 days, and the other 8 days, after inoculation. Diarrhoea occurred in one pair of piglets and oedema of the mesocolon was seen at post mortem examination of 5 piglets. Virus was isolated from the tonsil, ileum, colon and rectum of most of the inoculated piglets, but not from the liver, spleen, kidney, pancreas, brain, lung, bronchial or mediastinal lymph node, parotid salivary gland, mesenteric lymph or jejunum.

Protides of the mustelidae—II. Immunologic relatedness

1. 1. Immunoelectrophoretic (IE) analyses of serum proteins of fourteen species of the family Mustelidae and two species of the family Viverridae were performed with extensive reciprocal testing. 2. 2. Immunologic relatedness was assessed using the criteria of IE pattern complexity and precipitin arc definition. 3. 3. Using the above criteria, members of the subfamilies Mustelinae, Malinae and Lutrinae showed similar degrees of immunologic relatedness. 4. 4. The Mephitinae showed less immunologic cross-reactivity when tested against species of the other three subfamilies. 5. 5. An interpretation of data suggest that the Mustelinae, Melinae and Lutrinae probably shared a common ancestor for some time after the divergence of the line leading to the modern Mephitinae.

Antigenic relationships between strains of tobacco mosaic virus

The serological relationships between six strains of tobacco mosaic virus were studied with antisera from 40 rabbits bled at regular intervals during at least 8 mo. The extent of cross reactivity between strains was expressed by a serological differentiation index (SDI) equal to the difference between homologous and heterologous titers denoted as Neg Log 2. The extent of cross reactivity between two strains was determined in reciprocal serological tests, using antisera against each of the two strains. Average SDI values calculated from a large number of bleedings taken from different animals agreed closely with the corresponding SDI values calculated from reciprocal serological tests. The intraclass correlation coefficient between two sets of SDI values obtained in reciprocal serological tests was r′ = 0.95. A correlation coefficient of r = 0.75 was calculated between the serological relatedness expressed as SDI values and the extent of sequence homology in the coat protein of different strains.

Arginine gene cluster of Serratia marcescens.

Biochemical and genetic studies on the arginine-requiring auxotrophs derived from a Serratia marcescens strain were carried out. The arg mutants were classified into seven biochemical groups based on their growth response to five precursors of arginine biosynthesis and enzyme deficiency. Reciprocal transduction tests among these arg mutants divided them into three linkage groups, and the fine mapping in each of the groups by two- or three-point crosses revealed the following arrangement of loci. (1) arg44-thy11-lys1; (2) met1-glt2-argE-(arg19-arg51)-arg120-argG-argH; (3) arg33-pyr4. Five of the seven biochemically distinct arg mutants belonged to the second linkage group, and they constituted an agr-gene cluster. A characteristic feature of the arg-gene cluster of S. marcescens is that it involves argG, which was previously reported only in the Proteus group of Enterobacteriaceae.

Serologic differences in strains ofSporothrix schenckii

To obtain evidence that Sporothrix scheneckii enters the body by contact with contaminated materials, the antigenic property of strains from different sources was investigated. The reciprocal absorption test of the antisera against a soil isolate and a human isolate (KO 4606) showed that the absorbed antisera against KO 4606 possessed unique antigen(s) in addition to the common antigen of both strains. Twenty-three clinical isolates were tested with absorbed antisera. Not all of them possessed the unique antigen(s), but there were serologic varieties among S. schenckii strains, regardless of their sources, clinical type of the disease and the morphology of the yeast phase cells.

Rhinoviruses: an antigenic study of the prototype virus strains.

SummaryNinety rhinovirus types and a prime strain of RV 22 were compared in reciprocal serum neutralization tests. Neutralization was observed for each of the 91 homologous virus-serum mixtures. A single instance of reciprocal neutralization between two rhinovirus serotypes was noted. This reciprocal relationship, between RV types 29 and 44 was not altered by absorption with human liver powder. It is suggested that the relationship between RV types 29 and 44 may be a prime strain relationship similar to that described for RV type 22.Other antigenic similarities noted in this study were one-way crosses between RV types 1A and 1B, 9 and 32, and between types 36 and 58. The heterologous neutralizing activity of anti-RV 58 guinea pig serum was significantly reduced by absorption with human liver powder. Absorption did not materially alter the cross reactivity observed with the remaining antisera.

A fine structure map of the salmonella histidine operator-promoter.

Over 100 regulatory mutations linked to the histidine (his) operon of S. typhimurium have been isolated. They all map in a region estimated to be several hundred base pairs in length located at one end of the his operon ("the hisO region"). The mutations are located at sixteen recombinationally separable sites or are deletions encompassing several sites. Data obtained from pairs of reciprocal three-point tests show that "constitutive" (high enzyme levels) and "promoter-like" (low enzyme levels) hisO mutations are interspersed on the genetic map. In a few crosses, recombination was not observed to occur between markers shown to occupy different sites based on behavior in other recombination tests.

Assay and antigenic interrelationships of the recently isolated bovine herpesviruses, DN599, FTC, and V11

Various parameters of plaque production by the herpesviruses, DN599, FTC1, and V11 viruses in embryonic bovine trachea cells were investigated. Optimum plaque production by these viruses occurred when freshly seeded cells were infected and covered with a protamine-supplemented agar overlay. The rate at which DN599, FTC1, and V11 viruses were neutralized by specific antiserum was exceptionally slow but relatively high antiserum titers were observed. Reciprocal virus neutralization and indirect fluorescent antibody tests suggested that DN599, FTC1, and V11 viruses were antigenically related. Neutralization tests also revealed that the latter 3 viruses were not serologically related to infectious bovine rhinotracheitis virus.

Biological properties of two strains of Simian virus 40 isolated from patients with progressive multifocal leukoencephalopathy.

Biological properties of two strains of simian virus 40 (SV40) from brains of two patients with progressive multifocal leukoencephalopathy (PML) have been compared to those of a standard laboratory strain of SV40. Infectivity of both SV40-PML viruses was resistant to treatment with chloroform, low pH, and 50 C for 120 min. African green monkey kidney and BSC-1 cells were the most sensitive for viral replication, and cytopathology in these cultures was indistinguishable from that caused by SV40. Both viruses formed plaques in these cells. but, in African green monkey kidney cells, strain 1 virus produced plaques measuring 2 mm in diameter whereas strain 2 virus produced pleomorphic plaques varying from 1 to 10 mm in diameter. Hamster cells were not permissive for viral replication, and infection resulted only in viral transformation. Inoculation of human fetal glial cells resulted in a permissive lytic infection of one cell type and a persistent infection with only partial expression of the viral genome in the other. No morphological evidence of transformation was evident in the latter cells. Both strains of SV40-PML viruses were neutralized by commercial anti-SV40 serum, but in reciprocal kinetic neutralization tests differences in K values were noted when each was compared to SV40. Both viruses showed oncogenicity for hamsters, producing undifferentiated sarcomas when injected subcutaneously and choroid plexus papillomas after intracerebral inoculation. All hamster tumor cells contained intranuclear immunofluorescent tumor antigen. This was indistinguishable from SV40 T antigen in reciprocal staining reactions using hamster anti-T antibody induced by the two SV40-PML agents and SV40. These two human agents appear therefore to be new variants of simian virus 40.

A comparison of reciprocal progeny tests amongst Holstein-Friesian sires from Canada and the United States of America

SUMMARYThe test proofs of 29 Holstein-Friesian sires (12 Canadian and 17 US) with milking daughters in both Canada and the USA were compared. The mean test rating of the Canadian and US sires respectively was 125±74 kg and 265±57 kg higher in Canada than in the United States.These results were supported by others obtained in milking trials in Denmark and West Germany.The fat percentage of US Holstein progeny was higher in Canada and Europe than in the USA, suggesting that the low fat percentage of the US Holstein in its country of origin cannot be attributed simply to lack of genetic potential.It is suggested that the US Holstein be considered as a substitute for the Canadian for the improvement of milking performance in European Friesian populations.

Immunochemical cross-reactivity between the dissociated capsid proteins of PVY group plant viruses

Primary (4–5-week) and long-term (12-week) antisera were elicited against the pyrrolidine-dissociated capsid proteins (D-proteins) of tobacco etch virus (TEV) and potato virus Y (PVY), and subsequently used to ascertain the degree of immunochemical cross-reactivity between several PVY group viral D-proteins. Primary antisera were highly specific for homologous antigen. However, immunodiffusion and cross-absorption experiments with long-term anti-TEV D-protein and anti-PVY D-protein sera revealed pronounced cross-reactivity among the D-proteins of 14 different PVY group viruses. Furthermore, all cross-reactions involved the same antibody population except in the case of celery mosaic virus (CeMV) D-protein where but a portion of the antibody population was reactive. Spur formation in immuno-diffusion experiments was only observed among heterologous D-proteins when they were either adjacent to homologous D-protein antigen or (in an opposite direction) when compared with CeMV D-protein. Wheat streak mosaic virus dissociated protein, in contrast, was not found to be cross-reactive with PVY group D-proteins in reciprocal tests, and no cross-reactions were observed with the dissociated proteins of 6 additional viruses outside the PVY group.

Antigens of tumours induced by naturally occurring murine sarcoma virus (MSV-FBJ). I. Detection of group and type specific antigens by complement fixation.

Antigens associated with cells transformed in vivo by FBJ virus, a wild type murine sarcoma virus (MSV) complex originating from a spontaneously arising osteosarcoma in a CF1 mouse, have been partially characterized by complement fixation (CF). Using rat antisera against antigens specified by Gross leukaemia virus (GLV) the group specific (gs) antigen of C-type RNA murine tumour viruses was demonstrated in FBJ tumours as well as in GLV rat leukaemias, AKR lymphomata and sarcomata induced by MSV-H (Harvey), an MSV isolate of Friend-Moloney-Rauscher (FMR) subgroup specificity. Using mouse antisera against antigens present in FBJ cells the Gross (G) or wild type specificity of FBJ tumours was demonstrated by cross reactivity with antigens expressed on normal AKR lymphoid tissues and leukaemias. These antigens were absent from MSV-H induced sarcomata and in reciprocal tests mouse antisera to MSV-H failed to react with antigens present in FBJ tumour cells. No distinction between cellular and virion antigens expressed by FBJ cells was possible by CF although evidence for a cellular antigen with G specificity was obtained in tests using aged C57B1 antiserum containing a naturally occurring G antibody lacking significant virus neutralizing capacity. However, the likelihood that mouse FBJ antisera contain antibodies to type specific viral envelope antigens (VEA) as well as cellular antigen is discussed.