Mary E. Englert

THE ELECTRON MICROSCOPY OF RABIES VIRUS IN CULTURES OF CHICKEN EMBRYO TISSUES.

Abstract Cultures of chicken embryo tissue infected with the HEP Flury strain of rabies have been studied with the electron microscope. Sections of infected cells reveal within the cytoplasm round and elongated particles associated with masses of homogeneous material. Similar particles can also be seen budding from the cell membranes and free in extracellular space. Round and elongated particles were also seen in pellets from infected tissue culture fluid both by sectioning and by negative staining. The round forms have a wide size range and by negative staining sometimes show a fringed outer surface resembling myxoviruses. This structure has not been seen on the elongated particles. The particles described were not seen in uninfected cultures, and their appearance could be prevented by adding rabies immune serum to the inoculum. It has not been possible so far to correlate infectivity with one or both types of particles.

Suppression of type II collagen-induced arthritis by the intravenous administration of type II collagen or its constituent peptide α1, (II) CB10

Intravenous administration of Type II collagen to rats prior to immunization with Type II collagen suppresses hind paw inflammation, humoral response to Type II collagen, and the severity of the arthritic lesion. Suppression of inflammation and its severity as well as the humoral response can also be induced by the prior intravenous administration of alpha 1 (II) CB10 a cyanogen bromide peptide derived from Type II collagen. Suppression of arthritis is disease specific; intravenous administration of either Type II collagen or alpha 1 (II) CB10 does not have an effect on adjuvant-induced arthritis. These studies indicate that structural determinants of alpha 1 (II) CB10 (Mr 30,000), a peptide located near the carboxy terminus of the collagen molecule, can induce suppression and suggest that these determinants may be responsible for the suppression of arthritis when Type II collagen is administered intravenously.

Pretreatment of rats with anticollagen IgG renders them resistant to active type II collagen arthritis.

Intravenous administration of 24 mg of affinity-purified rat anticollagen IgG induced a polyarthritis in recipient rats within 48 hr. This polyarthritis was transient and hind paw diameters returned to normal values within 12 days. IgG and C3 could be detected on the articular cartilage by immunofluorescence up to 16 days after antibody administration. Administration of 24 mg of rat anticollagen IgG to these antibody-treated rats did not induce a second phase of polyarthritis. In addition, recovered rats that had been pretreated with antibody were resistant to arthritis when Type II collagen was administered intradermally. In these rats, serum anticollagen IgG levels were significantly lower than in control rats which were not treated with antibody. Pretreatment of rats with anticollagen IgG did not have an effect on the severity or the incidence of adjuvant-induced arthritis. In addition, pretreatment of rats with anticollagen IgG did not have an effect on the development of a humoral response to ovalbumin.

GAL virus: Its growth cycle in tissue culture and some of its properties

Abstract The GAL virus growth cycle has been determined by plaque assay and correlated with electron microscope observations of infected cells. The virus was found to have a long latent period and growth cycle, to be produced only within the cell nucleus, and to accumulate there. It also was found to be polyhedral in shape and ether stable and to resemble adenovirus in its intranuclear site of development, its morphology, and its ether stability. Data concerning its stability under various conditions of storage are included.

Studies on the effect of pentosan polysulfate on proteoglycan degradation by leukocyte neutral proteases

Abstract Pentosan polysulfate (SP-54), an anti-inflammatory agent, inhibits the degradation of proteoglycan by a leukocyte neutral protease preparation enriched with elastase. Under the assay conditions used, a 50 per cent inhibition is observed at approximately 3.5 × 10 −8 M pentosan polysulfate. Pentosan polysulfate, at concentrations up to 1 × 10 −5 M, does not affect the proteolytic degradation of protcoglycan catalyzed by trypsin, ehymotrypsin and pancreatic elastase. The inhibitory effect of pentosan polysulfate is most probably related to the interaction of the drug with the proteoglycan substrate. The resulting complex is stable to proteolytic degradation by leukocyte neutral proteases. This complex is readily dissociated by 0.5 M sodium chloride and the resulting proteoglycan can be subsequently degraded by the leukocyte protease preparation.

Correlation of structure with infectivity of influenza virus.

Abstract Using the technique of phosphotungstic acid negative contrast, standard productions of high titer influenza virus in embryonated eggs have been compared with “incomplete virus,” produced both by the von Magnus procedure of undiluted passage and by the procedure of Fazekas de St. Groth and Graham, who pretreated the embryos with potassium periodate. Most of the particles found in the third undiluted passage virus, with a titer of 106 ID50/ml in eggs, differed markedly from those found in a standard preparation with a titer of 109. These different particles were void of dense internal bodies and varied greatly in shape and size. In preparations grown in embryonated eggs pretreated with potassium periodate, where both the infectivity and hemagglutinin titers were low, the particles were mostly of a bizarre form without dense internal bodies and with sparsely spaced spines in their external coats. A combination of negative staining and metal shadowing indicated that particles not possessing the dense internal body were flat empty bags. Even the preparations with highest infectivity titers contained a considerable proportion of the baglike spiny structures. The nature of the internal dense granule has not been revealed, but tentative possibilities are discussed.

Passive transfer of collagen arthritis: Heterogeneity of anti-collagen IgG

Using a combination of affinity chromatography procedures, anticollagen IgG was fractionated into three distinct populations. One population reacted only to conformational determinants, another population reacted only to structural determinants, and the third population reacted to both conformation and structural determinants. When these populations were tested for their arthritogenicity, only those fractions that reacted to conformational and to conformational and structural determinants were active in inducing clinical arthritis. Immunofluorescence analysis of the hind paw of recipient rats indicated that antibodies directed only to conformational and to both conformational and structural determinants bound to articular cartilage and activated the complement system. Antibodies directed strictly to structural determinants did not bind to articular cartilage and were nonarthritogenic.

Propagation of mouse polyoma virus in a strain of mouse mammary tumor cells in vitro.

Summary 1) An established cell line originating from a spontaneous mouse mammary tumor is a convenient host in which to propagate and to assay polyoma virus in vitro. Cytopathic effects of the virus were first observed in cultures 6 days after infection and progressed to complete destruction of all cells by 12th day. Increasing cell destruction was accompanied by rise in tissue culture infectivity and hemagglutination titers. 2) Observations with electron microscope revealed presence of virus in infected cells beginning 6th day after infection. Virus particles were observed in the nucleus and occasionally in the cytoplasm. Particles averaged 30 mμ in diameter and did not show an internal structure.

Type II collagen arthritis: Identification of arthritogenic epitopes using fractionated anticollagen IgG

Affinity-purified anticollagen IgG was fractionated on purified cyanogen bromide-derived collagen peptide Sepharose. The antibody fraction bound to the peptides was eluted and tested for its ability to induce passive arthritis in recipients. Anticollagen IgG bound to peptide 5 (alpha 1(II)-CB8-10 and alpha 1(II)CB11-8) and to peptide 6 (alpha 1(II)CB11) were active in inducing passive arthritis. Other peptide bound fractions were inactive. These observations suggest that the arthritogenic domain in Type II collagen is restricted to alpha 1(II)CB11.

Studies on a leukocyte elastase inhibitor present in the culture medium of inflamed synovial tissue

Abstract The spent medium of cultured inflamed synovial tissue contains a potent inhibitor of leukocyte elastase. This leukocyte elastase inhibitor has no effect on leukocyte cathepsin G and pancreatic elastase is only marginally affected. The inhibitor is a glycoprotein, stable to heat, acid and reductive alkylation. Pretreatment of the inhibitor with either trypsin or chymotrypsin results in its inactivation.