Biomedical subjects

K R Parsons

Publications and source records attributed to K R Parsons.

At least 37 records · Page 2Linked to original sources

PubMed1993

A new bovine leukocyte antigen cluster comprising two monoclonal antibodies, CC43 and CC118, possibly related to CD1.

Two mAbs, CC43 (012) and CC118 (040), clustered together when the flow cytometric data for staining of target cells was analysed statistically. The antigen recognized was present on immature thymocytes but not mature T cells; it was expressed by B cells and monocytes but not by granulocytes. Two molecules were evident by SDS-PAGE run under reducing conditions. One had an M(r) of 44 kDa, the other an M(r) of 12 kDa. The smaller molecule was probably beta 2-microglobulin; the larger one was distinct from bovine CD1b and MHC Class I. The mAb may recognize the product of a previously unrecognized bovine CD1 gene and should be considered as a novel bovine mAb cluster. The molecule appeared to be polymorphic and distinct alleles may be expressed on Bos taurus and Bos indicus.

Animals↗

PubMed1993

Comparison of CD1 monoclonal antibodies on bovine cells and tissues.

A comparison was made of six mAbs within temporary clusters TC19 and TC28 that were previously established, or considered from unpublished data, as recognizing bovine and ovine CD1. All six immunoprecipitated a molecule of 46 kDa from iodinated thymocytes together with a second molecule of 12 kDa that appeared to be beta 2 microglobulin. mAb 20-27 (Workshop code 038) recognized a molecule expressed on bovine monocytes and B cells from bovine peripheral blood as well as thymocytes and cells with a dendritic morphology in sections. mAb CC20 (033) was shown to stain COS cells transfected with human CD1b cDNA and this mAb together with CC14 (not in workshop panel) and CC90 (007), which gave identical staining by flow cytometry and immunohistology, should all be regarded as being bovine CD1b mAb. The bovine CD1b molecule is expressed on bovine thymocytes and a proportion of cells with a dendritic morphology in tissue sections. Flow cytometric data with mAbs CC40 (039) and CC122 (043) were not sufficiently similar to data with mAb CC20 to allow the two mAbs to be regarded as CD1b although they did appear to be directed against bovine CD1 molecules. Furthermore, CC122 recognized a molecule expressed by a high proportion of cells in the lamina propria of the gut that was not recognized by the other mAbs. The findings indicate that the six mAbs recognize at least two and possibly four CD1 antigens.

Animals↗

PubMed1993

Identification of monoclonal antibodies specific for bovine leukocyte common antigen (CD45) together with a novel broadly expressed leukocyte differentiation antigen, BoWC11.

Ten mAbs that comprised temporary clusters TC5 and TC7, plus an additional mAb, CC171, were compared. All mAbs reacted broadly and stained antigen expressed on thymocytes as well as T and B cells in peripheral blood. The five mAbs CC1, CC171, 2E8, TD14 and TD15 precipitated molecules of 180, 205 and 220 kDa, and we conclude that they recognize the bovine leukocyte common antigen and are BoCD45 mAb. The three mAbs IL-A117, 1C10 and BAGB27A precipitated molecules of 86 and 63 kDa that were broadly expressed. It is proposed that these three mAbs should be regarded as a cluster (named BoWC11 within the Second Workshop) that is distinct from BoCD45.

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PubMed1993

Comparison of monoclonal antibodies with potential specificity for restricted isoforms of the leukocyte common antigen (CD45R).

Ten monoclonal antibodies (mAbs), that comprised temporary cluster TC1, and included a previously published CD45R mAb, were compared together with mAb IL-A116 which did not cluster with any workshop mAb. The ten mAbs of TC1 immunoprecipitate molecules with an M(r) of 220 and 205 kDa; sequential precipitation with a CD45 mAb indicates that these mAbs recognize restricted isoforms of the leukocyte common antigen. Cellular and tissue distribution suggests that mAbs within TC1 recognize at least two different specificities of the CD45 family of molecules. mAb IL-A116 precipitated a molecule of 180 kDa suggesting that it may recognize the CD45RO isoform of the leukocyte common antigen.

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PubMed1993

Identification of monoclonal antibodies specific for the gamma/delta TCR.

Twelve monoclonal antibodies (mAbs) formed temporary cluster TC36. mAb CACTB6A was included as a standard antibody that reacted with the gamma/delta T cell receptor (TCR). Eight of the mAbs, CACTB6A, CACT16A, CACT17A, CACTB12A, CACTB44A, CACT71A, CACT18A and CACT61A, immunoprecipitated a 47 kDa molecule indicating that they all recognize the gamma/delta TCR. Flow cytometric studies separated these mAbs into three groups that distinguish three different gamma/delta TCR. mAb BAQ72A, which fell within TC36, immunoprecipitated a 215 kDa molecule with a similar tissue and cellular distribution to BoWC1 mAb. mAbs CACT26A, CACT63A and CACT77A reacted similarly to each other by flow cytometry and immunohistology, but were distinct from the other mAbs in TC36. These three mAbs may recognize an activation molecule and form a distinct novel mAb cluster.

Animals↗

PubMed1993

Studies of monoclonal antibodies identifying two novel bovine lymphocyte antigen differentiation clusters: workshop clusters (WC) 6 and 7.

Analysis of flow cytometric staining of 50 target cells resulted in five monoclonal antibodies (mAbs) forming two adjacent clusters called temporary cluster (TC) 2. The five mAbs gave similar immunostaining of frozen sections, but flow cytometric analysis and the M(r) of molecules indicated that they comprised two distinct specificities. Mabs CC98, IL-A114 and IL-A53 all immunoprecipitated a molecule of 210 kDa that preclearing experiments with mAbs to the leukocyte common antigen (CD45) showed did not recognize isoforms within the CD45R family of molecules. The 210 kDa molecule was present on all CD2+ cells and B cells, but not expressed by WC1+ gamma/delta T cells. mAbs TH1A and TH18A precipitated molecules of 69 and 62 kDa which were present on cells expressing CD2, WC3 (B cells) and WC1 (gamma/delta T cells). It is proposed that these five mAbs should be considered as comprising two new bovine lymphocyte differentiation clusters, WC6 (mAbs CC 98, IL-A114 and IL-A53) and WC7 (TH18A and TH1A).

Animals↗

PubMed1993

A new non-lineage specific antigen with an M(r) of 115 kDa and 39 kDa present on bovine leukocytes identified by monoclonal antibodies within BoWC10.

Five mAbs out of a total of 189 submitted to the Second Workshop were shown to be similar when statistical analyses of flow cytometry data were performed. For the duration of the workshop the five mAbs were assigned to temporary cluster TC35. The mAbs precipitated two polypeptides by SDS-PAGE under reducing conditions. One had an M(r) of 115 kDa, the other an M(r) of 39 kDa. The antigen recognized was present on thymocytes, a subpopulation of CD2+ T cells and a major subpopulation of B cells. The antigen is upregulated after long-term activation with concanavalin A. It is proposed that the mAbs in TC35 should be regarded as a single cluster identifying a novel leukocyte differentiation antigen in cattle. These mAbs were accepted as a new workshop cluster BoWC10.

Animals↗

PubMed1993

In vivo role of lymphocyte subpopulations in the control of virus excretion and mucosal antibody responses of cattle infected with rotavirus.

T-cell control of primary rotavirus infection and mucosal antibody responses to rotavirus was studied with monoclonal antibodies (MAb) to deplete gnotobiotic calves of CD4+, CD8+, BoWC1+, or both CD4+ and CD8+ lymphocytes prior to infection with rotavirus. Injection of these MAb produced specific reductions in circulating and tissue lymphocyte subpopulations. Following infection, control calves developed fecal immunoglobulin M (IgM) and IgA antibodies and serum IgM and IgG1 antibodies; there was no IgG2 antibody produced. Anti-CD4-treated calves had reduced fecal and serum antibody responses to rotavirus compared with control calves. The IgM response was less affected than the other isotypes. Calves concurrently injected with MAb to CD4 and CD8 had antibody responses similar to those of calves injected with anti-CD4 antibody alone. No effect on serum or fecal antibody levels was seen when MAb to CD8 or BoWC1 were injected alone. Virus excretion was significantly increased in calves depleted of CD8+ cells. Depletion of CD4+ cells or BoWC1+ cells had no effect on virus excretion. Calves depleted of both CD4+ and CD8+ cells excreted amounts of virus similar to those of calves depleted of CD8+ cells alone. Onset and duration of virus excretion were not affected by any of the MAb treatments. We conclude that a CD8+ cell population is involved in limiting primary rotavirus infection, while CD4+ or BoWC1+ (gamma/delta+ TcR) lymphocytes are not. Furthermore, CD4+ lymphocytes (but not CD8+ or BoWC1+ lymphocytes) were shown to be important in the generation of mucosal, as well as systemic, antibody responses.

Animals↗

PubMed1993

Variation in rotavirus virulence: a comparison of pathogenesis in calves between two rotaviruses of different virulence.

Variation in virulence between two bovine rotaviruses was investigated using ten female and ten male 10-day-old gnotobiotic calves of five breeds or cross breeds that were inoculated with a virulent strain or a strain of low virulence. Similar numbers of infectious viral particles were detected in feces of calves inoculated with either virus, but diarrhea, xylose malabsorption, and reduction of villus height occurred only after inoculation with virulent virus. The mean percentage of the area of the villus epithelium per villus immunostained for rotavirus antigen was eight times greater in calves inoculated with virulent virus, and the mean percentage of villi on which immunostained enterocytes were detected was twice as large in calves inoculated with virulent virus than in calves inoculated with the virus of low virulence. Mean crypt death and mean crypt cell production rates were increased after inoculation with either virus. Virulence was associated with extensive spread of infection through the small intestine, preferential colonization of the proximal small intestine, and marked damage to enterocytes and villi. The virus of low virulence infected the proximal small intestine poorly, and although it infected more enterocytes in the mid and distal small intestine and replicated in them, causing cytopathic effects, it did not damage intestinal structure and affect function.

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PubMed1992

A study of the basis of virulence variation of bovine rotaviruses.

Rotaviruses are enteric pathogens of cattle but sub-clinical infections are common. Virulence variation has been identified with bovine rotaviruses and some rotaviruses replicated without clinical signs in non-immune calves. The rotavirus genome is composed of eleven segments of double-stranded RNA and the fourth largest segment codes for a non-glycosylated surface protein, VP4, which has been linked with virulence. In the present study the biological basis of rotavirus virulence variation was studied in vivo and compared with the known properties of the fourth gene. Calves were inoculated orally with a virulent rotavirus or a rotavirus of low virulence which multiplied but failed to cause diarrhoea. They were taken for necropsy at intervals of 2 days after inoculation. Clinical signs, virus in faeces and the percentage of infected small intestinal epithelium were determined. Damage to the small intestine was assessed by measurement of villus heights and crypt-cell production rates. Virulence was associated with a greater level of colonization of the small intestinal epithelium, greater enterocyte damage and preferential infection of the upper small intestine. The fourth gene determines the ability of rotaviruses to spread in vitro and the finding that virulence was associated with greater colonization in vivo raises the possibility that this gene may have an important role in rotavirus virulence.

Animals↗

PubMed1992

L-selectin expression differentiates T cells isolated from different lymphoid tissues in cattle but does not correlate with memory.

L-selectin (LECAM-1, LAM-1) was expressed by a high proportion of CD4+ and CD8+ T cells, as well as almost all of the gamma delta T-cell receptor (TcR)+ (WC1+) T cells, isolated from blood, lymph nodes or tonsils. CD4+ T cells in the lamina propria of the gut villi and CD8+ T cells in the villous epithelium as well as the majority of WC1+ T cells in the gut mucosa were L-selectin-. The proportion of T cells from Peyer's patches that synthesized the molecule was intermediate between the value for blood and gut mucosa. Expression of L-selectin therefore marks T cells in cattle with a distinct tissue distribution that correlates with its function as the peripheral node homing receptor. The proportion of CD4+ and CD8+ T cells in the circulation that were L-selectin+ decreased with age. Unlike CD45R, expression of L-selectin was not related to CD4 T-cell memory as judged by proliferation in transformation assays to soluble antigen. Three-colour immunofluorescent staining demonstrated four subpopulations of CD4 and CD8 T lymphocytes in peripheral blood mononuclear cells (PBMC) that were CD45R+, L-selectin+; CD45R+, L-selectin-; CD45R-, L-selectin+; CD45R-, L-selectin-. CD4(4) memory cells were CD45R- and L-selectin+ or L-selectin-. Taken with earlier studies the reported observations demonstrated that only one of the four phenotypes of the CD4+ T cells in blood is present in the lamina propria of the gut villi and these are CD45R-, L-selectin-. Two of the four phenotypes of CD8+ T cells were present in the gut epithelium; these were CD45R+, L-selectin- or CD45R-, L-selectin-. Expression of the bovine molecule was not rapidly down-regulated on T cells following activation by exposure to phorbol myristate acetate.

Aging↗

PubMed1991

Distinction of naive and memory BoCD4 lymphocytes in calves with a monoclonal antibody, CC76, to a restricted determinant of the bovine leukocyte-common antigen, CD45.

A murine IgG1 monoclonal antibody (mAb), CC76, has been produced that, based on findings of the relative molecular mass of polypeptides that it recognized, staining of leukocytes in blood and tissues, and the biological properties of the T lymphocyte subpopulations with which it reacts, is considered to identify an isoform of the leukocyte common antigen (LCA) family of molecules in cattle. The mAb is more similar to human CD45R which detect products requiring the presence of the B exon within the LCA gene and to the anti-rat mAb MRC-OX22, than to CD45RA or CD45R0. mAb CC76 reacts with an antigen expressed by subpopulations of cells in bovine blood that express BoCD2 and either the BoCD4 or BoCD8 antigens. T cells that express the gamma/delta T cell receptor identified with mAb to BoWC1 antigen did not react with CC76. The molecule detected is expressed on B cells but not on monocytes or granulocytes. Only 2% of cells in thymic suspensions stained with mAb CC76. Immature cortical thymocytes that were BoCD1+ did not react with CC76 and 90% of the cells in thymic suspensions that were CC76+ had the phenotype of mature thymocytes. These cells were primarily in the medulla. The LCA isoform detected thus appears to be acquired by mature cells shortly before emigration from the thymic medulla into the periphery. Expression of the molecule detected by mAb CC76 on cells from lymph nodes was similar to that in blood, but expression on cells from the gut mucosa was quite different. Almost all, 95% and 93% respectively, of the BoCD4+ cells in the gut mucosa or discrete Peyer's patches were CC76-. A greater proportion of BoCD8+ cells from these sites, 35% and 26%, expressed the antigen. Lymphocytes from animals that had been immunized with Trypanosoma brucei were sorted into BoCD4+, CC76+ and BoCD4+, CC76- populations and cultured in vitro with the variable surface glycoprotein antigen from the parasite. Lymphocyte transformation responses were entirely within the CC76- population indicating that the mAb distinguished naive from memory BoCD4+ T cells in cattle. Major histocompatibility complex (MHC) class I-restricted cytotoxic precursor cells that expressed the BoCD8 antigen sorted from cattle that were immune to Theileria parva were both CC76+ and CC76- indicating that different isoforms of the LCA may be expressed on MHC class I- and class II-restricted memory cells and that BoCD8 memory cells are heterogeneous with respect to the LCA isoform that they express.

Animals↗

PubMed1991

Individual antigens of cattle. Bovine CD1 (BoCD1).

The results support the view that these mAbs can be regarded as equivalent to CD1 mAbs in man, as has been concluded for certain of them previously. Although mAb 20-27 did not cluster with the other mAbs, the finding that it precipitated the same molecule from thymocytes indicates that it should be included in BoCD1. Studies in man indicate that more than one CD1 molecule exists (Boumsell and Knowles, 1988; Cattoretti et al., 1988) and a similar situation is apparent in cattle with 20-27 probably being equivalent to CD1c and the others to CD1b.

Animals↗

PubMed1991

Competitive binding with putative Bo5 (CD5) cluster of monoclonal antibodies.

The relationship of seven monoclonal antibodies, putatively to the Bo5 (CD5) antigen, was tested. Five of the mAbs were confirmed to be directed against the Bo5 antigen. Three mAbs, CC29, BLT-1 and 8C11, effectively blocked binding to bovine PBM of mAb CC17, previously reported to be directed against this antigen. MAb 8-3F4 also blocked binding of mAb CC17, but less effectively than the others. MAbs IL-A67 and 79-5 did not inhibit binding of mAb CC17 because of antibody allelic specificity or technical reasons.

Animals↗

PubMed1991

Investigating monoclonal antibodies to bovine "null" cell antigens using two-colour immunofluorescence.

Eighteen monoclonal antibodies (mAbs) putatively to non T4/T8 (null) cell antigens were tested by two-colour immunofluorescence and antibody binding inhibition (blocking), with one selected mAb (CC15) that previous studies had indicated to be specific for null cells. None of the other mAbs blocked binding of CC15 to lymphocytes. Three main patterns of reaction were observed in two-colour immunofluorescence studies: mAbs that stained the same cells as CC15, mAbs that only stained a sub-population of the cells that stained with CC15 and mAbs that stained a sub-population of the cells that stained with CC15 but also some cells that did not react with CC15.

Animals↗

PubMed1991

Immunohistology of workshop monoclonal antibodies to the bovine homologue of CD1.

Six monoclonal antibodies putatively to the BoCD1 antigen were compared by immunohistology on cryostat sections from a range of tissues. The different staining patterns observed allowed the mAbs to be placed in three groups (a) 20-27, (b) CC13, CC14, TH97A and (c) CC20, CC40. An ovine mAb VPM5 did not stain bovine tissues sufficiently strongly to enable a comparison with the other CD1 mAbs.

Animals↗

PubMed1991

Follicle associated epithelium of the gut associated lymphoid tissue of cattle.

The morphology of the gut-associated lymphoid tissue of the small and large intestine in three gnotobiotic calves was examined by scanning and transmission electron microscopy, and the distribution of specialized membranous cells present in the follicle associated epithelium was defined. Isolated follicles remaining in the ileum of a cow after involution of the continuous Peyer's patch were examined by scanning electron microscopy. The presence of membrane-bound particles, reported to be exclusively associated with the continuous Peyer's patch, was investigated in other gut-associated tissue of the small and large intestine of the calf. The presence of two types of follicle associated epithelium in the small intestine of the calf was confirmed, and the follicle associated epithelium of the large intestine proved to be a homogeneous population of specialized membranous cells, similar to that of the continuous Peyer's patch of the small intestine. In the discrete Peyer's patches, some specialized membranous cells were completely hidden by adjacent enterocytes and could only be identified by cytoplasmic extensions into the intestinal lumen. In the proximal part of the continuous Peyer's patch, a transitional zone was detected where the follicle associated epithelium of some doomed villi was composed of a homogeneous population of specialized membranous cells, while the epithelium covering other doomed villi consisted of a mixture of absorptive and specialized membranous cells, usually only found in the discrete Peyer's patches. Membrane-bound particles were observed associated with gut-associated lymphoid tissue in the small and large intestine.

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PubMed1989

In vivo depletion of BoT4 (CD4) and of non-T4/T8 lymphocyte subsets in cattle with monoclonal antibodies.

The effect on certain immune responses of depleting two distinct lymphocyte subpopulations in vivo by inoculating calves with monoclonal antibodies (mAb) was examined. An mAb directed against the BoT4 antigen (the bovine homologue of CD4) effectively removed the BoT4+ lymphocytes from peripheral blood mononuclear cells (PBM). Compared to controls, treated calves showed a reduced antibody response to human O red blood cells and to ovalbumin. PBM prepared from BoT4-depleted animals also had a significantly reduced ability to respond in vitro to the mitogens phytohemagglutinin, concanavalin A and pokeweed mitogen. An mAb directed against a second numerically large bovine lymphocyte subpopulation i.e. BoT2-, BoT4-, BoT8- (CD2-, CD4-, CD8-), that may be homologous to the CD4-, CD8- cells in man and rodents that synthesize the gamma/delta+ T cell receptor, was also used for in vivo depletion. Compared to controls, calves depleted of this subpopulation showed an enhanced antibody response. The proliferative response of PBM to pokeweed mitogen was also significantly increased but responses to concanavalin A and phytohemagglutinin remained unchanged. The results suggest this lymphocyte subpopulation has a nonspecific suppressor activity acting on B cell responses either directly or through an effect on T helper cells. The non-T4/T8 cells are found extensively in the epithelium and lamina propria of the mucosa of the alimentary tract but not in T cell areas of the lymph nodes, tonsil and spleen. These non-T4/T8 cells may thus be, or contain, an intraepithelial lymphocyte population with a suppressor function.

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