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Chickens vaccinated with two doses of a bivalent Haemophilus gallinarum bacterin were protected against seven strains of the organism. Vaccinated and unvaccinated birds with antibody to Mycoplasma gallisepticum had increased HI titers when challenged with H. gallinarum. Birds positive for antibody to Mycoplasma gallisepticum which were not challenged showed no increase in HI titer.
A new generation of "bivalent" gp120-based vaccines, effective against subtype B and subtype E viruses, has been developed. Antisera from rabbits and humans immunized with these vaccines are able to neutralize macrophage tropic and T-cell tropic viruses grown in activated peripheral blood mononuclear cells (PBMCs). These vaccines are now available for efficacy trials to determine the role of humoral immunity in providing protection against human immunodeficiency virus type 1 (HIV-1) infection.
UNLABELLED: The purpose of this study was to compare the toxicity and efficacy of two-step radioimmunotherapy using a bispecific anticarcinoembryonic antigen (CEA)/anti-diethylenetriamine pentaacetic acid (DTPA) antibody (F6-734 bispecific monoclonal antibodies (BsMAbs) and an 131I-di-DTPA-TL bivalent hapten with F(ab')2 fragments of the same directly labeled anti-CEA 131-F6. METHODS: Eight groups of nude mice subcutaneously grafted with the human TT medullary thyroid cancer cell line were injected once tumor volume reached about 200 mm3. Two groups received 37 or 92.5 MBq (1 or 2 nmol) 131I-di-DTPA-TL 48 h after injection of 2 or 4 nmol F6-734 BsMAb and two groups received 37 or 92.5 MBq (250 microg) 131I-F6. Four control groups were treated respectively with (a) 92.5 MBq nonspecific 131I-734 fragments, (b) 92.5 MBq 131I-di-DTPA-TL 48 h after injection of a mixture of irrelevant F6-679 (anti-CEA/anti-histamine) and G7A5-734 (anti-melanoma/anti-DTPA) BsMAb, (c) 250 microg nonradiolabeled F6, and 250 microg F6-734 BsMAb and then 48 h later 1.25 nmol of nonradiolabeled hapten. A control group received no injections. Toxicity was evaluated by determining animal weight and the number of leukocytes and platelets, and efficacy by variation in tumor volume and thyrocalcitonin during a 90-d period. Histological analysis of tumors and statistical studies were performed. RESULTS: The time required for the tumor to double in size was respectively 57 and 86 d with 37 and 92.5 MBq F6-734/131I-di-DTPA-TL and 44 and 65 d with 37 and 92.5 MBq 131I-F6. Changes in thyrocalcitonin levels were parallel to those in tumor volume. Weight loss was 5%, leukocyte nadirs respectively 1640+/-838 and 1560+/-1160/mm3 and platelet nadirs 1.46+/-0.52 10(6)/mm3 and 0.73+/-0.38 10(6)/mm3 after injections of 37 and 92.5 MBq F6-734/1311-di-DTPA-TL. Weight loss was respectively 8% and 16%, leukocyte nadirs 50+/-100/mm3 and 175+/-50/mm3 and platelet nadirs 0.71+/-0.18 10(6)/mm3 and 0.48+/-0.11 10(6)/mm3 after injections of 37 and 92.5 MBq 131I-F6. CONCLUSION: Two-step radioimmunotherapy was as efficient as the one-step system and markedly less toxic.
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Bispecific CD3xCD19 antibodies and CD28 co-stimulating antibodies were used to activate T cells in bone marrow aspirates (n = 8) of children with B cell-derived acute lymphoblastic leukemia. Bone marrow specimens were incubated for 10 days with CD3xCD19 bispecific and CD28 antibodies. Changes in the numbers of T lymphocytes and tumoral B cells as well as surface expression of T cell-activation markers were determined by flow cytometry, and cytokines (human IFN-gamma, IL-2, IL-4 and IL-12) were measured in the cell culture supernatant. In 7 of 8 bone marrow samples, an increase in the number of CD4- and CD8-positive T lymphocytes was found, which correlated with an up-regulation of T cell-activation markers. Additionally, we demonstrated a decrease of tumoral B cells in 3 samples and enhanced cytotoxic T-cell activity against autologous malignant B cells. ELISpot analyses in an autologous Epstein-Barr virus model showed that bispecific antibodies (CD3xCD19+CD28) were more potent at generating T-cell responses against autologous and allogeneic tumoral targets than a combination of monospecific antibodies (CD3+CD28). Thus, T-cell targeting by CD3xCD19 bispecific and CD28 antibodies may be used to eliminate leukemic B cells ex vivo and reconstitute immunological control of residual malignant disease by the induction of anti-tumoral T-cell responses.
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The dissociation equilibrium constants (Kd values) of dequalinium (2) and the monoquinolinium compounds 1a and 1b have been determined from competition equilibrium radioligand binding with [125I]apamin on rat brain synaptic plasma membranes (SPMs). Dequalinium binds to the channel with 2 orders of magnitude higher affinity than 1a or 1b, suggesting that both quinolinium groups are needed for potent and selective SKCa channel blockade. The trisquinolinium compound 3 (1,1'-[5-[4-(4- aminoquinolinium-1-yl)but-1-yl]non-4-en-1,9-diyl]-bis-(4- aminoquinolinium)) has been synthesized and tested for inhibition of the afterhyperpolarization of rat sympathetic neurones and on the binding assay. Compound 3 shows approximately one order of magnitude higher potency than 2, being the most potent non-peptidic SKCa channel blocker reported so far (Kd approximately 30 nM). The higher affinity of 3 compared with 2 may be due to direct binding of the third quinolinium group to the channel or may arise from a reduction of the unfavorable entropy of binding via an increase of the "local concentration" of quinolinium groups.
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The mutagenic potential of hyperthermia was examined employing a spermatocyte test on males heat stressed continuously for 2, 3. or 5 days. Stress conditions were 35 +/- 1 degrees C and 65 +/- 3% relative humidity. Males were sacrificed and meiotic preparations made from the testes at various intervals following removal from the stress environment. In this way, chromosome damage could be monitored in all premeiotic and early prophase I stages of spermatogenesis. Results of this study revealed a significant increase in the incidence of X and Y univalents at metaphase I. The significance of this finding is discussed.
Hydroxyapatite, the major component of bone, demonstrates significant reactivity with metals. Knowledge of spatial structure and energy data of the molecule helps understand the binding of metals by hydroxyapatite and elucidate the chemical and physical properties of such complexes. We used HyperChem software (Hypercube Inc.) to analyze the structure of hydroxyapatite when the central calcium atom is replaced by one of the metal ions (Mg, Cu, Zn, Fe, Cr, Mn) marked by us in bone. Our results show that hetero-ionic exchange affects composition and leads to deformation of hydroxyapatite crystals. Replacement was accompanied by changes in bond lengths between oxygen and calcium atoms in the hydroxyapatite molecule and by displacement of groups of atoms surrounding the central calcium atom. The use of molecular modeling as a computational tool enabled a preliminary and theoretical understanding of chemical structure without the need for laboratory tests.
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