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Biomedical subjects

A Lengyel

Publications and source records attributed to A Lengyel.

At least 37 records · Page 2Linked to original sources
PubMed1992

Latex agglutination and adenoviruses. I. Detection of polyclonal antibodies by latex agglutination test.

A latex agglutination (LA) test was developed for the detection and measurement of polyclonal anti-adenovirus antibodies. Latex particles, coated with purified hexon, penton or fibre antigens displayed specific agglutination with 21 rabbit immune sera directed against the different antigens and the complete virus of 10 human and 2 animal adenovirus types. The sensitivity of LA was compared to that of passive haemagglutination, complement fixation (CF) and immunodiffusion reactions. In experiments with immune sera as well as with human serum samples the sensitivity of LA test proved to be in the same range as that of CF test. Because of its easy and rapid performance (slide agglutination within 4 min) LA method may substitute for CF reaction in serological adenovirus diagnosis.

Adenoviridae↗
PubMed1990

Changes in plasma testosterone, thyroxine and triiodothyronine in relation to sperm production and remex moult in domestic ganders.

Changes in plasma testosterone (T), thyroxine (T4), triiodothyronine (T3), semen output and remex moult were studied in domestic ganders. A bimodal pattern in both plasma T and sperm concentration was observed during the annual cycle. Ganders started to produce semen at the end of January; maximum semen volume (0.32 +/- 0.04 ml) and sperm concentration (148 +/- 38 x 10(3)/mm3) were reached in March and a marked decrease was observed after mid-April, when the moult of the remiges began. Plasma T3 levels peaked in February (9.7 +/- 0.6 nmol.l-1) and this peak coincided with maximum T concentrations (9.8-10.4 nmol.l-1). Elevated levels of T4 were found from late February until mid-April (31.0-33.6 nmol.l-1). Plasma T concentration was low at all stages of remex moult and regrowth. Decreased T4 levels were found in ganders during remex regrowth from the "brush" to half of the full primary growth stage. Higher plasma T4 levels were found before and after this stage of the moult. A reverse pattern was observed for T3 concentrations.

Animals↗
PubMed1990

Characterization of an intermediate adenovirus strain.

An intermediate strain of human adenovirus of subgenus D was investigated by type specific serological reactions and restriction endonuclease analysis. The latter method showed the strain identical to the prototype strain of human adenovirus type 9 as well as did serum neutralization tests. In contrast with the previous methods haemagglutination inhibition tests showed the strain related to both the prototypes strains of human adenovirus 9 and 13.

Adenoviruses, Human↗
PubMed1988

Antigenic relationship between human and animal adenovirus hexons determined by means of monoclonal antibodies directed against bovine adenovirus type 2 hexon.

Eight monoclonal antibodies (MAbs) directed against bovine adenovirus (BAV) 2 subtype B hexon were studied with 12 different hexon types of human adenoviruses (AV) belonging to 5 different subgenera using indirect ELISA, passive hemagglutination (HA), and gel diffusion assays. Two hexon types of animal origin (BAV3 and SAV16) were investigated, too. The reactivity of the MAb IV.F3 was the broadest, i.e. in ELISA and HA experiments it reacted with all hexon types studied. Based on these results as well as on the results of gel diffusion assays, this MAb should recognize the genus specific epitope of adenovirus hexons. Three MAbs (CA12, III.B11, and A12) could recognize different epitopes showing intersubgenus or intertype specificities. In spite of the fact, that all the eight MAbs proved to be bound by the hexon of ORT/111 (BAV2 subtype B) blotted onto nitrocellulose filter, four of the eight MAbs (BB7, BH5, II.A9, and IV.F5) failed to react with any human, and animal hexon types used in the present experiments. The results suggest that a gradient of antigenic relationship may exist between BAV2 hexon and the hexons of human serotypes.

Adenoviridae↗
PubMed1988

Characterization of monoclonal antibodies to adenovirus type 35 hexon.

Twenty three monoclonal antibody-rich ascitic fluids (MIAFs) to human adenovirus (AV) type 35 hexon were studied by indirect ELISA using various tracer systems, passive haemagglutination (HA) as well as gel diffusion techniques. Eleven different human heterologous hexon types in addition to the homologous one, and two animal adenovirus (AV) hexons were used to determine the reactivity patterns (RPs) of the monoclonal antibodies (MoAbs). Based on the cross-reactivity with the different hexon types, the MoAbs exhibited genus, subgenus and type specificities; furthermore, a variety of intersubgenus and intertype specificities could be found. Fifteen of the MoAbs reacted in ELISA, but not in passive HA, suggesting that certain epitopes on the hexons bound to red blood cells were not available for the MoAbs in question. Four MoAbs were able to form a precipitin line with the hexon antigen in gel diffusion. Two of the four (MoAbs 35H10 and 35H51) formed with the homologous AV35 hexon a single confluent precipitin line only. In spite of the origin of these MoAbs from different hybrid cells (clones) their specificity was probably identical when recognizing the type-specific epitope of the AV35 hexon. The other two MoAbs (35H15 and 35H26) with a broad RPs were able to precipitate not only the homologous but also different heterologous hexon types.

Adenoviruses, Human↗
PubMed1987

Determination of different antigenic sites on the adenovirus hexon using monoclonal antibodies.

Eighteen mouse ascitic fluids containing monoclonal antibodies (MAbs) directed against crystallized hexon of adenovirus (AV) type 1 were used to map the antigenic structure of the capsomer in reciprocal competitive binding ELISA. With the help of peroxidase-labelled MAbs at least nine epitopes (epitope clusters) located on three distinct antigenic sites were identified on the hexon. Epitope on antigenic site I recognized by two MAbs could be the genus specific antigenic determinant based on the broad reactivity patterns of the MAbs. Epitopes on the antigenic site II recognized by fifteen MAbs could be divided into seven epitope clusters according to the competition patterns. Antigenic site III recognized by one MAb completely differs from the antigenic site I and on the basis of one-way blocking with all the MAbs specific for antigenic site II, should be also different from the latter one. The data suggest that the seven epitope clusters of antigenic site II contain partially overlapping epitopes and may be a part of a large single immunodominant antigenic region on AV 1 hexon as well as on hexons of heterologous types.

Adenoviruses, Human↗
PubMed1987

Monoclonal antibodies to adenovirus type 35 hexon.

A panel of 37 monoclonal antibodies (MAbs) directed against adenovirus type 35 (AV35) hexon was studied by indirect enzyme-linked immunosorbent assay (ELISA) and passive hemagglutination (HA) methods. Nine heterologous hexon types and the homologous type were used to determine the reactivity pattern (RP) of the MAbs and to study the antigenic relationship among the different hexon types. Eleven types of RPs were shown using ELISA and seven types were shown using the HA test. In the case of six MAbs, the RPs were identical in both assay systems; 31 MAbs showed some differences when the results of the two methods were compared. The common epitopes of the different hexon types studied seem to be characterized as genus, subgenus, intersubgenus, and intertype specificities. The type-specific determinant of AV35 hexon could be detected by several MAbs. The antigenic relationship seems to be closer between the two oncogenic subgenera (A and B) of adenoviruses, whereas the antigenic relationship to AV35 hexon is somewhat looser for subgenera D, and E. Hexon types of subgenus C showed the greatest differences in antigenic structure compared with the AV35 hexon.

Adenoviruses, Human↗
PubMed1987

Distribution pattern of adenovirus hexon epitopes in infected cells determined with monoclonal antibodies by immunofluorescence analysis.

Two monoclonal antibodies (MAbs) specific for two distinct epitopes on the human adenovirus type 1 (AV1) hexon were used to determine the subcellular localization of hexon epitopes in the infected HEp-2 cells by indirect immunofluorescence. On the basis of cross-reactivity pattern of MAbs, presumably one of the epitopes is genus specific and the other should be intertype specific. The epitopes, i.e. the adenovirus hexons could be detected throughout the cell and could display different accumulation forms. Fluorescence appeared either in the cytoplasm only or both in the nucleus and the cytoplasm. In the cytoplasm the hexons could be found in diffuse or perinuclear distribution or accumulated into discrete spots. In the nucleus they formed granules or clusters or were diffusely distributed causing a bright fluorescence of the whole nucleus. The different accumulation forms appeared at the same time in different cells of a culture, but in one given cell the fluorescence always appeared first in the cytoplasm.

Adenoviruses, Human↗
PubMed1986

Grouping of monoclonal antibodies to adenovirus hexons by their cross-reactivity.

Thirty two mouse ascitic fluids containing monoclonal antibodies (MAbs) directed against the hexon of human adenovirus type 1 were examined. The type and degree of cross-reactivity (CR) of the MAbs were determined by ELISA and hemagglutination methods with 10 heterologous hexon types. The similarity and the dissimilarity of the MAbs was also characterized by the correlation coefficient calculated from their reactivity values. On the basis of these, the 32 MAbs could be divided into five groups and fourteen individual MAbs, which altogether recognized 19 distinct epitopes. One of the recognized epitopes is the genus specific epitope of adenovirus hexons; the others are interspecies specific ones which can be found on the surface of the different hexon types in characteristic, mosaic-like combinations. The type and degree of CR of the MAbs lead to the conclusion that there exists a close antigenic relationship among the members of subgenus C of human adenoviruses and there is also a definite antigenic relationship between subgenera C and D. Hexons belonging to the oncogenic subgenera A and B display a much looser antigenic relationship with subgenus C.

Adenoviruses, Human↗
PubMed1986

Multiple copies of identical epitopes on the adenovirus hexon.

A double monoclonal antibody (MAb) sandwich enzyme-linked immunosorbent assay (double MAb ELISA), which uses the same MAb as solid-phase immunosorbent (capture MAb) and as detector MAb (peroxidase-labeled), was developed to quantify the specific epitopes of adenovirus hexon. Four MAbs directed against crystallized adenovirus type 1 (Ad h 1) hexon were tested by this assay with homologous and different heterologous hexons. The lowest reacting concn with the homologous and heterologous hexon types both in direct and double MAb ELISA was determined and compared. At least two copies of four different epitopes were identified by the MAbs. Evidence is presented that more than one copy of identical or closely related epitopes exist on the homologous as well as on the heterologous hexon molecules. However, their presence could be detected only in higher concn of hexon preparations of subgenera A, B and D.

Adenoviruses, Human↗
PubMed1986

Detection of adenovirus hexon using monoclonal antibodies for antigen capture in ELISA.

The feasibility of using monoclonal antibodies to capture specific viral polypeptides in double monoclonal antibody (MAb) sandwich ELISA has been demonstrated. Ten MAbs with different reactivity patterns were used for antigen capture and four of them were labelled with horse radish peroxidase and used for the detection of specifically bound hexon antigen and for the determination of the lowest reacting hexon concentrations. Differences have been found in the effectiveness of the different MAbs used for capturing or detecting the antigen. Two assay systems (MAbs 1A3/1A3 and H12/1A3), which were the most sensitive for the hexon types studied could be useful for detection of the adenovirus hexons. Assay system MAb 2D1/2A1 and several combinations of MAb 2B2 proved to be specific for subgenus C.

Adenoviruses, Human↗
PubMed1985

Differentiation of adenovirus hexon epitopes with monoclonal antibodies by gel diffusion assays.

Nine monoclonal antibodies (MAbs) directed against crystallized human adenovirus type 1 (Ad h 1) hexon were tested with purified homologous and heterologous hexon preparations by gel diffusion. Six MAbs formed a single line with the homologous hexon in a 2-well pattern, and 3 MAbs formed lines only in biclonal combinations with an appropriate MAb. All of the 6 precipitating MAbs formed a continuous line of complete identity when tested simultaneously against homologous and different heterologous hexons. With Ad h 1 hexon a line of double partial identity (double spur) was formed when some pair combinations of 2 MAbs were placed in 2 juxtaposed wells. Other MAbs in the adjacent wells formed a line of identity. The MAbs could be divided into 2 antibody groups (groups A and B) based on this phenomenon. Members of antibody groups A and B apparently identified 2 sterically distinct epitopes: one of them is presumably the genus-specific epitope of the hexons (group A) and the other(s) should be intertype-specific epitope(s). Thus, the gel diffusion method can be used for selecting pairs of MAbs for their specificity to sterically independent epitopes. Mixtures of 2 MAbs belonging to the different antibody groups formed double lines with Ad h 1 hexons. Members of group A showed some helper effect to the members of group B for their precipitin line formation.

Adenoviruses, Human↗
PubMed1985

Delineation of antigenic determinants of adenovirus hexons by means of monoclonal antibodies.

60 hexon-specific mouse hybridoma clones were selected by using crystallized hexon capsomers of human adenovirus type 1 as immunizing and selecting antigen. The reactivities of the monoclonal antibodies were tested with purified hexon preparations from 10 human adenovirus types by enzyme-linked immunosorbent assay and passive hemagglutination techniques. The reactivity patterns delineated a total of 41 adenovirus-type-1-related determinants present on a number of heterologous hexons in different interspecies combinations. The pattern of interspecies specificities did not coincide with the current grouping of adenoviruses into subgenera.

Adenoviruses, Human↗
PubMed1985

Reactivity of mouse ascitic fluids containing monoclonal antibodies directed against adenovirus hexon.

Thirty-two mouse hybridoma ascites were produced, containing hexon specific monoclonal antibodies, using crystallized hexons of human adenovirus type 1 as immunizing and selecting antigen. The reactivity of the ascitic fluids was tested with hexon preparations of 11 different human adenovirus species (serological types) belonging to 4 different subgenera by ELISA and passive haemagglutination (HA) methods. By these methods the 32 hybridoma antibodies showed 4 and 12 distinct reactivity patterns (type of cross-reactions) respectively. In the positive cases significant differences could be detected in the titres of the hybridoma antibodies in both ELISA and HA. It can be assumed that adenovirus type 1 hexon-related epitopes are present on a number of heterologous hexons in characteristic (interspecies) combinations for the given heterologous hexon and that a gradient of relationship may exist among the antigenic structures of hexons of the different adenovirus species.

Adenoviruses, Human↗
PubMed1985

A sensitive method for detection of polyclonal and monoclonal antibodies against the adenovirus hexon.

Chromic chloride and tannic acid methods were elaborated to bind purified adenovirus hexons to sheep red blood cells (SRBC). Either method gave very sensitive haemagglutination (HA) with adenovirus antisera, but treatment with tannic acid was more sensitive. Using this method, specific antibodies present in polyclonal immune sera against adenoviruses and adenovirus hexons, and the reactivity of monoclonal antibodies directed against adenovirus hexon type 1 were tested to 11 adenovirus types. With certain types, the high haemagglutination titres exceeded those obtained with ELISA, while with other types they remained slightly below the ELISA titres. The elaborated passive HA method with tannic acid is easily accomplished and may serve as an effective and useful tool in the study of both polyclonal and monoclonal antihexon antibodies.

Adenoviruses, Human↗
PubMed1984

Further analysis of the effects of cholecystokinin octapeptides on avoidance behaviour in rats.

Experiments were performed to examine the acute effects of cholecystokinin octapeptides and fragments on the active and passive avoidance behaviour of rats following peripheral and central administration. Both the sulphated (CCK-8-SE) and non-sulphated cholecystokinin octapeptide (CCK-8-NS) and also the COOH-terminal tetra-, penta-, hexa- and heptapeptides of cholecystokinin octapeptide facilitated the extinction of active avoidance behaviour and retention of passive avoidance behaviour. This latter effect of cholecystokinin octapeptides was reversed by anxiolytic chlordiazepoxide pretreatment, showing that in these test situations cholecystokinin octapeptides are able to modify fear-motivation or arousal of the animals; their effect is at least partly similar to that of the neuroleptic substance haloperidol. Subcutaneous treatment with CCK-8-SE or CCK-8-NS appeared to be 3-10 times more effective than intraperitoneal treatment. Following intracerebroventricular administration, 100-300 times lower doses were needed to cause a behavioural effect similar to that after subcutaneous injection. Microinjection of CCK-8-SE or CCK-8-NS in the fmol dose range into the nucleus accumbens facilitated the extinction of active avoidance behaviour and attenuated the retention of passive avoidance behaviour, while microinjection of these peptides into the central amygdaloid nucleus caused opposite effects on these behavioural tests. It seems that the neuroleptic-like effects of cholecystokinin octapeptides are mediated through the nucleus accumbens, and the opposite action (non neuroleptic-like) through the central amygdaloid nucleus.

Amygdala↗