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K M Thompson

Publications and source records attributed to K M Thompson.

106 records · Page 6Linked to original sources
PubMed1987

Requirements for the establishment of heterohybridomas secreting monoclonal human antibody to rhesus (D) blood group antigen.

Stable cell lines producing monoclonal human antibodies can be derived by fusion of Epstein-Barr virus-transformed peripheral blood B lymphocytes (LCL) with the mouse myeloma line X63-Ag8.653. One major limitation to this approach is the establishment of LCL cultures with sufficient cells secreting the specific antibody. In this study on the production of anti-D(Rh) antibodies, the kinetics of the appearance of specific EBV-transformable precursors in the circulation was followed after secondary immunization, and the optimum time for obtaining B cells for the establishment of suitable LCLs was found to be during the period 2-4 weeks post boost. During this period the probability of obtaining LCLs suitable for fusion is significantly higher than from blood samples collected randomly. From these high-titre LCLs the success rate for the fusion process was high. The specific EBV target cells are presumably memory cells produced after the peak of the antibody response and having only a transient appearance in the circulation.

Antibodies, Monoclonal↗
PubMed1987

Radio-immunoassay of the functional activity of anti-D (Rh) preparations using a human monoclonal 125I-labelled anti-D.

The prophylactic effect of anti-D in the prevention of maternal immunization to the D antigen of the Rh system depends in the first instance on its ability to bind to fetal Rh-positive red cells. The functional activity of the injected anti-D in this respect is dependent on both the plasma concentration and functional affinity constant of the antibody, and both factors should be taken into account in assessing IgG anti-D preparations for clinical use. A radio-immunoassay utilizing 125-I-labelled human monoclonal anti-D has been developed which measures the amount of antibody bound to red cells after the addition of an aliquot of the test anti-D preparation. The assay is thus a functional test in that it measures the ability of the anti-D to react with the antigen. The functional activity of the test anti-D is compared to that of the international standard, and the concentration is then expressed in terms of microgram-equivalents, that is, its equivalence in functional terms to the stated amount of international standard. The radio-immunoassay was compared to the currently used agglutination assay, and the results were found to give good agreement in 18 out of the 21 samples assayed.

Antibodies, Monoclonal↗
PubMed1987

Differences between the activities of human monoclonal IgG1 and IgG3 subclasses of anti-D(Rh) antibody in their ability to mediate red cell-binding to macrophages.

Four IgG1 and three IgG3 human monoclonal antibodies specific for the blood group D(Rh) antigen were tested for their ability to mediate red cell-binding to macrophages in vitro. The IgG3 monoclonals were found to opsonize at a density of approximately 100 molecules per red cell, whereas the IgG1 antibodies were only active at a level of 10,000 molecules per cell. There was no substantial difference between the two IgG subclasses in their ability to bind to Fc receptors on macrophages and it is suggested that the more potent opsonic activity of IgG3 is the result of the relatively long hinge, leading to greater accessibility to the Fc receptor binding site on the Fc piece.

Antibodies, Monoclonal↗
PubMed1986

The efficient production of stable, human monoclonal antibody-secreting hybridomas from EBV-transformed lymphocytes using the mouse myeloma X63-Ag8.653 as a fusion partner.

The mouse myeloma X63-Ag8.653 was fused to peripheral blood lymphocytes (PBL) from apparently healthy individuals, autoimmune patients and volunteers immunised with Rhesus (D) positive erythrocytes. Fusions were performed with or without prior transformation of PBL with Epstein-Barr virus (EBV). Using untransformed PBL, under the best conditions a mean fusion frequency of 8.4 X 10(-6) was obtained, with 22% of the resulting hybridomas secreting human immunoglobulin. Fusions with EBV-transformed cells gave fusion frequencies of 1.0 X 10(-4), with 85-90% of hybridomas secreting human immunoglobulin. The heterohybridomas formed in both cases cloned efficiently and had doubling times of 24-30 h. The heterohybridomas secreted human IgM, IgG and IgA of both kappa and lambda isotypes and culture supernatants contained up to 50 micrograms ml-1 of human immunoglobulin. Mouse immunoglobulin was not detected in the culture supernatants. 28 hybrids were selected for vigorous growth and antibody production by repeated cloning. Immunoglobulin synthesis was stabilised in 26 of these hybridomas after two or three cloning steps. The heterohybridomas have been successfully grown in large volumes for periods up to 15 months. It is concluded that the mouse myeloma X63-Ag8.653 is a suitable fusion partner with EBV-transformed B cells in the efficient production of human monoclonal antibodies.

Animals↗
PubMed1986

Production of human monoclonal IgG and IgM antibodies with anti-D (rhesus) specificity using heterohybridomas.

Heterohybridomas secreting human IgM and IgG anti-D antibodies of the rhesus blood group system have been established by fusion of EBV-transformed anti-D secreting cells with the mouse myeloma cells X63-Ag8.653. Both classes of antibody reacted with all Rh-positive cells, some Du cells but not with Rh-negative or DB cells. Concentrations of both antibodies reached between 25 micrograms/ml and 50 micrograms/ml in the culture supernatants. The cell lines have been maintained in culture for 14 months and have been shown to be suitable for large-scale production of antibody.

Animals↗
PubMed1970

Isolation of rubella virus from abortion material.

Rubella virus was isolated from the fetus or products of conception in 29 out of 32 cases (91%) terminated because of clinical maternal rubella proved or supported by laboratory findings in the first trimester of pregnancy. Virus was isolated from similar material from only 3 out of 19 (16%) other clinical cases of rubella in which the laboratory findings were inconclusive or against the diagnosis or in which no laboratory tests were done. Virus was found in the amniotic fluid if the fetus was infected and there was no evidence that the placenta was any real barrier to fetal infection.

Abortion, Therapeutic↗
PubMedDate not supplied

Violence in G-rated animated films.

CONTEXT: Children's exposure to violence in the media is a possible source of public health concern; however, violence in children's animated films has not been quantified. OBJECTIVE: To quantify and characterize violence in G-rated animated feature films. DESIGN: Violence content was reviewed for all 74 G-rated animated feature films released in theaters between 1937 and 1999, recorded in English, and available for review on videocassette in the United States before September 1999. MAIN OUTCOME MEASURES: Duration of violent scenes, type of characters participating in violent acts (good, neutral, or bad), number of injuries/fatalities, and types of weapons used for each film. RESULTS: All 74 films reviewed contained at least 1 act of violence (mean duration, 9.5 minutes per film; range, 6 seconds-24 minutes). Analysis of time trends showed a statistically significant increase in the duration of violence in the films with time (P=.001). The study found a total of 125 injuries (including 62 fatal injuries) in 46 (62%) of the films. Characters portrayed as "bad" were much more likely to die of an injury than other characters (odds ratio, 23.2; 95% confidence interval, 8.5-63.4). A majority of the violence (55%) was associated with good or neutral characters dueling with bad characters (ie, using violence as a means of reaching resolution of conflict), and characters used a wide range of weapons in violent acts. CONCLUSIONS: Our content analysis suggests that a significant amount of violence exists in animated G-rated feature films. Physicians and parents should not overlook videocassettes as a source of exposure to violence for children. JAMA. 2000;283:2716-2720.

Child↗
PubMedDate not supplied

Heterogeneous RF structures between and within healthy individuals are not related to HLA DRB1*0401.

To study variations in Rheumatoid Factor (RF) autoantibodies between and within healthy individuals, we have produced and analysed the variable heavy chain (VH) regions of 18 new monoclonal IgM RFs from the peripheral blood of two healthy subjects before and after immunization with tetanus toxoid (TT). The majority of these RFs used germline genes of the VH3 family, but RFs of the VH1, VH2 and VH7 families were also found. No RF of the VH4 RF is found. Fourteen different VH germline (GL) genes encoded the RFs, suggesting an extraordinary heterogeneity in structure. Consequently, changes in RF V region structures following immunization were difficult to identify. There were, however, structural differences between RFs from the two donors. RFs from one donor (IP) used more lambda light chains than RFs from the other donor and previously described RFs. In addition, 50% of the RFs from donor IP were encoded by GL genes frequently found to encode RFs from patients with Rheumatoid Arthritis (RA) but not described in RFs from other healthy subjects. The predominant use of VH3 RFs in the two healthy donors contrasts with the over-expression and expansion of VH1 RFs in one previously described healthy immunized donor. There are thus large individual differences in RF structures, which might be related to the immunological status, environment or genetic background of the donors. However, since these three donors are all HLA DRB1*0401, it is unlikely that this HLA type, associated with seropositive RA, accounts for the individual differences.

Adult↗
PubMedDate not supplied

Cold agglutinin activity is common among human monoclonal IgM Rh system antibodies using the V4-34 heavy chain variable gene segment.

BACKGROUND: The V4-34 gene segment is commonly used by human monoclonal IgM alloantibodies against blood group antigens and by cold-reactive red cell autoantibodies with anti-I or anti-i specificity. This study was conducted to determine whether cold agglutinin activity is found among the V4-34-encoded alloantibodies. STUDY DESIGN AND METHODS: Fifty-four human IgM monoclonal antibodies (MoAbs) against Rh system antigens were tested for cold agglutinin activity against red cells lacking the relevant Rh system antigen and for reactivity with tissue I and/or i antigens using immunohistochemistry. The findings were correlated with the utilization of the V4-34 segment as determined in an enzyme-linked immunosorbent assay with an antibody (9G4) that is specific for this gene product and were also correlated with other serologic properties. RESULTS: Of the MoAbs, 59 percent were 9G4-positive. Of the 9G4-positive subset, 16 and 44 percent agglutinated native adult (express I) and cord (express i) cells, respectively, at 4 degrees C; these levels rose to 84 and 94 percent, respectively, with the use of papain-treated cells. The red cell antigens recognized at 4 degrees C were cleaved by endo-beta-galactosidase, which is consistent with their being I and i. Of the 9G4-positive subset, 53 percent bound to tissue i antigen. These reactivities were not found among 9G4-negative MoAbs. Endo-beta-galactosidase treatment of red cells enhanced Rh system antibody agglutination by 9G4-negative MoAbs. CONCLUSION: Anti-I/i reactivity is common among IgM Rh system MoAbs and is shown only by the V4-34-encoded subset. This finding has implications for the use of MoAbs for Rh system typing of blood.

Agglutinins↗
PubMedDate not supplied

Workers' breath as a source of perchloroethylene (Perc) in the home.

Wallace et al. (1991a) measured elevated levels of perchloroethylene (Perc) in the homes of six dry cleaning workers who used Perc in the workplace. This paper considers the hypothesis that dry cleaning workers introduce Perc into their homes by exhaling Perc accumulated in their bodies during the work day. We simulated worker exposure considering current occupational guidelines, uptake and body burden using a physiologically-based pharmacokinetic (PBPK) model for Perc, and home concentrations using a simple model for a "typical" home. These results suggest that workers' body burdens of Perc may be sufficient to explain elevated home concentrations. The implications of these results, for design of exposure monitoring studies, are discussed, along with some other policy implications.

Air Pollution, Indoor↗