[An evaluation of the China-made HIV antibody test reagents]

This paper reports the results of the evaluation of the China-made HIV antibody screening test reagents, including the IF and IE reagents prepared by the Institute of Virology, CAPM, the ELISA reagent prepared by the Shanghai Institute of Biological Products. Based on the results, the sensitivities of the IF and IE are from 91.2% to 96.9%; the specificities, from 94.6% to 97.3%. Due to the low HIV prevalence in China, the predictive values of negative of these reagents are up to 100%; but the predictive values of positive are very low. It is suggested that these reagents can be used for HIV antibody screen testing in China. The package of some reagents should be improved, the price of some reagents should be decreased.

Induction of tumor necrosis factor by macrophage colony-stimulating factor in vivo

The effect of human urinary colony-stimulating factor (CSF-1) on the production of tumor necrosis factor (TNF) in vivo was assessed. Purified CSF-1 was administered i.v. to rabbits 4 days prior to injection with lipopolysaccharide (LPS). TNF in the serum prepared from rabbits bled 90 min after LPS injection was measured using cytotoxicity assays employing mouse L929 cells and antirabbit TNF monoclonal antibody. The results indicated that CSF-1 was able to induce the production of TNF in vivo and had a synergistic effect with Propionibacterium acnes.

Intestinal immunity to Trichinella spiralis is a property of OX8- OX22- T-helper cells that are generated in the intestine

The phenotype of T-helper cells conferring protection against Trichinella spiralis (Ts) was studied using adoptive transfer procedures and T-helper cell subsets isolated by monoclonal antibodies. With these techniques OX8- OX22+ and OX8- OX22- T-helper cell populations were isolated from thoracic duct lymph (TDL) of infected rats three-five-fold more concentrated than in unfractionated lymph. The OX8- OX22- cell subset alone transferred enhanced rejection of adult worms from the intestine. The origin of protective OX8- OX22- cells was examined in mesenteric lymphadenectomized (MX) rats. After MX, protective cells were found in the cell population draining directly from the intestine on Days 2-3 after infection. Protective cells first appeared in the mesenteric lymph node (MLN) and efferent lymph at Day 3. MX rats rejected T. spiralis at the same time as intact controls and showed enhanced rejection when immune TDL were transfused. No evidence was found for a direct role of the MLN in the generation or expression of parasite rejection. Depletion of migrating OX8- OX22- blast cells by 48-hr drainage of TDL did not influence the expression of an anamnestic response to challenge infection. This suggests that an intestinally resident cell population has a substantial role in mediating primary worm rejection and anamnestic immunity. Day 2 OX8- OX22- cells from MX rats proliferated in response to the presentation of adult and muscle larvae antigens in vitro. We conclude that protection resides in the OX8- OX22- T-helper cell subset that is produced and functions in the intestine.

Early pulmonary and hemodynamic effects of a chest wall burn (effect of ibuprofen)

The cardiopulmonary effects of a third-degree scald burn involving the anterolateral chest wall was compared with a burn of equal size (30% of total body surface) to the flanks in anesthetized sheep with lung lymph fistulas. The chest-burn group was characterized by immediate decreases in cardiac output (6.5 to 3.0 L/min), central venous pressure (5 mm Hg to 0 mm Hg), pulmonary wedge pressure (10 mm Hg to 6 mm Hg), and urine output 1.5 ml/kg/hr to less than 0.5 ml/kg/hr. The temperature of pulmonary artery blood increased from 38 to 42 degrees C and plasma prostacyclin increased from 20 to 200 pg/ml. These changes were significantly different from those seen in the body sheep with burns. Initial fluid requirements necessary to restore filling pressures were 50% greater in the sheep with chest burns than in the sheep with body burns. An early decrease in static lung compliance was also seen after chest burn that was not the result of increased lung edema. A progressive decrease in compliance, urine output, and stroke output was also seen in the later postburn period (6 to 7 hours), which was significantly improved by a chest wall escharotomy. Postmortem analysis in the chest-burn group revealed a significantly increased malondialdehyde content, a reflection of increased oxygen radical-induced lipid peroxidation relative to the body burn. Pretreatment of the chest burn with ibuprofen, 12.5 mg/kg, prevented the initial vasodilator and lung compliance changes so that early cardiopulmonary status was identical to that seen with a body burn alone. Ibuprofen also decreased the lung tissue malondialdehyde content. We conclude that a burn involving the chest wall results in cardiopulmonary abnormalities, not seen after a body burn of a comparable size, which appear to be due to hyperthermia and an increased release of prostacyclin and O2 radicals.

A new mutation in IVS-1 of the human beta globin gene causing beta thalassemia due to abnormal splicing

A G to T transversion at the fifth nucleotide of the first intervening sequence (IVS-1) of the beta-globin gene has been identified in cloned beta-thalassemia genes of two unrelated individuals, one of Mediterranean and the other of Anglo Saxon ancestry. In each patient the mutation was present in a different beta globin gene framework, defined by intragenic restriction site polymorphisms, thereby suggesting the occurrence of independent mutations. The study of the RNA products of one of these cloned genes, after transfer and transient expression in HeLa cells, showed partial inactivation of the normal donor splice site of IVS-1 and activation of two major and one minor cryptic splice sites. Only one of the two major cryptic sites was utilized in a cell-free splicing extract. The effects of this mutation on messenger RNA (mRNA) splicing are similar to that of another beta thalassemia gene with a G to C transition at the same position.

Frequency of expressed immunoglobulin light chain genes in lipopolysaccharide-stimulated BALB/c spleen cells

Variants of four hybridoma lines secreting antibodies specific for either trinitrophenyl (TNP) or sheep erythrocytes (SRBC) were isolated which have lost either the specific heavy (H) chain or the specific light (L) chain. They were fused to lipopolysaccharide-stimulated mouse spleen cells and the resulting secondary hybridomas were screened for the restoration of the original antibody specificity. Antibody activity was 37 times more frequently restored with fusion lines donating H chain than with those donating L chain. We obtained a variety of different (spleen cell derived) L chains in association with one H chain and one specificity. We found that those L chains originally associated with a given H chain were rescued most often. Their frequencies were 1:74 and 1:490 for an anti-SRBC- and an anti-TNP-restoring kappa L chain, respectively. Two most commonly observed V-J kappa combinations in one anti-SRBC complementation group were detected with a 5- and 30-fold reduced frequency in two anti-TNP groups, indicating somatic diversification of kappa chains. It is shown that the Sp7/HK line resumes anti-TNP activity with a mutated, non-germline lambda 1 chain, which was found in 30% of lambda 1-expressing hybridomas.

Optimization of the culture medium composition for the antibody response of mouse spleen cells

The Mishell-Dutton culture system for in vitro primary antibody response of mouse spleen cells was used to optimize the amino acid composition of RPMI 1640 media. Each of the 20 amino acids was tested over a broad range of concentrations always leaving the remaining 19 amino acids unaltered (i.e. at the formula recommended concentration). In several instances, higher plaque-forming cell responses were obtained with an amino acid concentration that was either higher or lower than that recommended: (a) the optimum concentration for valine, glutamine, and lysine lies considerably above the recommended one, (b) the optimum concentration for leucine as well as for several other amino acids lies below the recommended concentration, and (c) the optimum concentration for arginine corresponds exactly to the recommended concentration. The second round of optimization, i.e. combining of two conditions that individually yielded an improved response often caused a decrease of response. The possibility is discussed that for an optimal response a ratio of two or several amino acids rather than the absolute concentration of any one amino acid is of importance.

Different ways to modify monoclonal antibodies

In this paper we summarize experiments which were undertaken to create altered antibody molecules. Three different approaches were used. Established hybridoma lines were re-hybridized to mouse spleen cells to generate arrays of secondary hybridomas which express one particular heavy chain and one specificity together with a multitude of different light chains. In such hybrids the influence of light chains to the antibody combining site and the influence of affinity to antibody effector functions can be studied. Another way to obtain altered antibodies was the selection of cells producing less lytic IgM. With this technique we obtained (among many other variants) a series of mu-deletion products which were used to map the fine specificity of rat anti-mouse mu monoclonal antibodies. Both the anti-mu antibodies and the deletion variants were used to assign the Clq binding to the fourth C mu-domain demonstrating the power of mutant IgM in the structure-function analysis. In a third series of experiments we show the feasibility of generating new antibody combining sites by the methods of molecular genetics. The variable region gene of a heavy chain was placed in front of a kappa-constant region gene. The plasmid construct was transferred into mouse myeloma lines which stably express a variable heavy-constant light chain protein. Upon fusion with a light chain producing line, chimaeric light chain dimers with a functional antibody combining site were secreted. These experiments demonstrate that new series of man-made antibody molecules can be made in the future.

Variable-region sequences of five human lambda-chain proteins reacting with an idiotypic antibody to the MCG Bence-Jones protein

An antibody to the V-region of BJ protein MCG has been used to detect other human lambda-chains with similar idiotypic specificities. Five such proteins have been found and sequenced. They show relatively strong sequence homologies to some segments of the MCG V-region. The results of this study indicate that L-chains which contain short segments of their V-regions that are identical can be readily detected by the use of appropriate antisera.

Establishment of three human liver carcinoma cell lines and some of their biological characteristics in vitro

Three cell lines derived from liver carcinoma specimens of two male and one female operated patients have been successfully established in vitro and designated by the names of BEL-7402, BEL-7404 and BEL-7405. In the course of the establishment (from the 2nd transfer onwards) studies were made to characterize them. The doubling time of cell population was found to be 20--26 hr. They formed tumor nodules upon heterologous transplantation. They appeared as epithelial-like cells in morphology and showed, in addition to desmosomes, the presence of cytoplasmic tonofibrills which were typical of epithelial cells by electron microscopy. The ultrastructural features were different from normal human liver cells, but similar to clinical hepatoma cells. They had hypotriploid chromosone number with one abnormally long acrocentric chromosome present in all 3 cell lines and additional small acrocentric chromosome and chromosome fragment in BEL-7405 line of cells. AFP were detected intracellularly by the indirect immunofluorescent method. LDH isoenzyme showed a pattern different from that of human adult liver, but similar to those of embryonic liver and clinical hepatoma with the increase of the percentage of LDH-1 (H-type) at the expanse of LDH-5 (M-type), i.e. with a higher H/M ratio. The results suggest the 3 lines of liver carcinoma cells as rapidly growing and not well differentiated epithelial-like malignant cells.