Control of established experimental allergic encephalomyelitis by inhibition of tumor necrosis factor (TNF) activity within the central nervous system using monoclonal antibodies and TNF receptor-immunoglobulin fusion proteins

Tumor necrosis factor (TNF) activity was inhibited during the development of actively-induced, chronic relapsing experimental allergic encephalomyelitis (CREAE) in Biozzi AB/H mice, using a mouse TNF-specific (TN3.19.12) antibody and bivalent human p55 and p75 TNF receptor-immunoglobulin (TNFR-Ig) fusion proteins. The development of disease could be inhibited when repeated doses of antibody were administered prior to the anticipated onset. It has now also been shown that a therapeutic effect is evident even when antibody is administered after the onset of clinical signs, further indicating an important role for TNF in pathogenic effector mechanisms in CREAE. Although biologically-active TNF was not detected in the circulation, TNF-α was detected in lesions within the central nervous system (CNS). This suggested that the CNS may be the main site for TNF-specific immunomodulation and was supported by the observation that intracranial injection was significantly more potent than that administered systemically, for both antibody and TNFR-Ig fusion proteins. The fusion proteins were as effective as antibody at doses 10—100-fold lower than that used for antibody, reflecting their higher neutralizing capacity in vitro. Although treatment was not curative and relapse inevitably occurred in this model if treatment was not sustained, the data indicate that anti-TNF immunotherapy, especially within the CNS, can inhibit CREAE and may, therefore, be useful in the control of human neuroimmunological diseases.     

Age-related reductions in rat atrial high affinity choline uptake, ACh synthesis, and ACh release. A brief note

We have developed a rat atrial mince preparation that can take up choline, acetylate it, and then release acetylcholine in a depolarization-dependent manner. We demonstrate that aging appears to reduce the functional cholinergic activity in this tissue, which may be important for understanding how senescence alters the regulation of cardiac activity.     

Platelet-induced tolerance in the production of heteroantisera to human leukemia-associated antigens.

A method is described for raising antisera to human leukemia cells of an individual patient in mice rendered tolerant with cyclophosphamide to platelets obtained from the same patient. The resulting antisera are able to distinguish serologically between leukemic blast cells and remission cells of patients with acute leukemia and may be recognizing leukemia-associated antigens. The antisera are similar in activity to antisera raised following tolerance-induction with remission leukocytes, but larger volumes of anti-leukemia antiserum can be raised using the more easily obtainable platelets. This technique provides further evidence that human platelets share many of the antigens present on human leukocytes.     

Repeated immunization with plasmid DNA formulated in poly(lactide-co-glycolide) microparticles is well tolerated and stimulates durable T cell responses to the tumor-associated antigen cytochrome P450 1B1

Injection of microparticle-encapsulated DNA elicits immune responses to plasmid-encoded antigens in mice and humans. Cytochrome P450 CYP1B1 (CYP1B1) is a member of the CYP1 P450 enzyme family that is overexpressed in a variety of solid tumors. The work described herein was performed to study the kinetics of stimulating T cell responsiveness with an encapsulated DNA encoding CYP1B1 and provides support for the clinical development of this formulation. Immunization of HLA-A2/Kb transgenic mice with human CYP1B1 encoding plasmid DNA formulated in poly(lactide-co-glycolide) (PLG) microparticles elicits CD8+ T cells that respond to human CYP1B1-positive target cells. The duration of the immune response, the effect on the immune response of multiple injections, and the safety of repeated injections were studied. These results show that the PLG-encapsulated DNA therapeutic elicits durable immune responses to CYP1B1, the responses are dependent on repeat immunization, and that the formulation is well tolerated.     

Immunobiologic heterotypic activity associated with viral and soluble components of bovine virus diarrhea virus

Summary The V and S antigens of bovine virus diarrhea (BVD) virus were studied by pig inoculation experiments to determine the basis for the bovine virus diarrheahog cholera heterotypic relationship. BVD virus infected tissue cultures were harvested and separated by ultracentrifugation and ultrafiltration. V antigen was prepared by Tween-ether-urea inactivation of virus. S antigen was quantitated in filtration samples and in density gradients by specific complement fixation. Pigs inoculated with crude, concentrated V antigen survived virulent hog cholera (HC) virus exposure. However, V antigen partially purified by ultracentrifugation failed to protect pigs. Neutralizing antibody to BVD, but not to HC, was synthesized in inoculated pigs following HC exposure. S antigen separated by 10 m, ultrafiltration and purified by potassium tartrate density gradient ultracentrifugation protected pigs from virulent HC. No BVD or HC antibody was detected at the time of HC virus exposure but HC antibody was produced at an accelerated rate following exposure. It thus appeared that an S antigen less than 10 m in size having a density between 1.05 and 1.10 g/ml which was produced during BVD virus replication in cells initiated the potential for a protective response.     

Allergens in the white and yolk of hen's egg. A study of IgE binding by egg proteins

The radioallergosorbent test (RAST) was used to compare the IgE binding of egg white and yolk, and allergenic proteins were detected by immunoelectrotransfer ('Western blotting'). The main allergens were found in egg white, but for a large proportion of the egg-sensitive patients, yolk contained specific IgE-binding constituents. For blood sera from 36 patients, there was a positive correlation between the results of RAST for egg white and for yolk. Lysozyme was found to be an allergen for some patients. The effect of heating on the allergenicity of egg white was examined and the allergenicity of hen egg white was compared with that of a duck egg. The allergens in yolk were associated with each of the three yolk fractions, and several of the proteins in the low-density lipoprotein fraction bound IgE.