ANTITOXOPLASMIC EFFECT OF IMMUNE SWINE SERUM REVEALED IN THE CULTURE OF SWINE LEUKOCYTES

Samples of buffy coat obtained from pigs actively immunized with Toxoplasma gondii and from a normal pig were cultivated separately in immune and normal swine sera, and the multiplication of toxoplasms in these cultures was studied. In the presence of immune serum, multiplication of toxoplasms was inhibited. The inhibition by immune serum was observed in the cultures of leukocytes derived from both immunized and normal pigs. On the contrary, in the presence of normal serum, toxoplasms multiplied abundantly in the cultures of leukocytes derived from immunized and normal pigs. These findings suggest that circulating immune substances will play a leading role in immunity against toxoplasmosis. The antitoxoplasmic effect of immune serum hardly reached to toxoplasms which had previously penetrated inside leukocytes. The antitoxoplasmic effect shown in the present study proved to be heat-stable, thus was considered different from the neutralizing antibody reported by SABIN and OLITZKY. However, the difference between the two is not yet elucidated

IMMUNOLOGICAL STUDIES ON THE INFECTIOUS CANINE HEPATITIS VIRUS : II. HEMAGGLUTININ

Experiments on the hemagglutination reaction by ICH virus were performed. The results are summarized as follows : 1) Two strains of ICH virus, "MATSUDA" and "Woc-4", agglutinated erythrocytes of human and guinea pigs under certain conditions. 2) HAT was affected by many environmental factors such as pH and electrolyte concentration of the reaction mixture, incubation temperature, concentration of erythrocytes and so on. Optimum conditions for the reaction were determined in respect to these factors. 3) Heat stability of infecting virus particle, CFA and hemagglutinin was studied and the relationship among these three components was discussed on the basis of the results of adsorption and elution experiments. 4) Normal dog sera were found to contain different amounts of normal inhibitor and hemagglutinin. Some methods to remove these substances are now under investigation. The authors wish to express their gratitude to Dr. OCHI, Tokyo University, for his helpful support in providing the strain of ICH virus

A CINEMATOGRAPHIC STUDY OF THE PENETRATION OF CULTURED CELLS BY TOXOPLASMA GONDII

Cinematographic observation with phase contrast microscopy was undertaken to elucidate a course of penetration of cultured cells by Toxoplasma gondii (RH strain). The results are summarized as follows : 1) The parasites which moved toward the cells showed active, irregular movements. No penetration was observed by less active or completely inactived parasites. 2) In the course of penetration of the cell membrane, the parasite attached itself to the cell membrane at a pole of its major axis. The attached portion of the parasite formed a rostrum with which it seemed to bore a small hole in the cell membrane through which it entered the cytoplasm. The hole or invagination must be smaller than the parasite because when passing through, the parasite was constricted. The time required for penetration of the cell averaged about 40 seconds. 3) Following the penetration, the parasites moved slowly in direction of the cell nucleus, but none were observed to penetrate the nuclei. 4) No common, definite cellular response was observed but, in general, the movement of the cytoplasmic granules surrounding the parasites decreased with time. 5) Escape of toxoplasma from the infected cell was observed, which was due to the movement of toxoplasma itself. Since the cell from which the toxoplasma escaped was found rather inactive, it is probable toxoplasma is highly sensitive to the nutritional condition of host cell

PURIFICATION STUDIES ON THE INFECTIOUS CANINE HEPATITIS VIRUS : II. VIRAL PARTICLES AND THEIR CHARACTERISTICS REVEALED BY MODIFICATION OF THE PURIFICATION PROCEDURE

The picture of the infectious canine hepatitis virus particle derived from infections tissue culture fluid and cells has been clearly demonstrated by a modified purification procedure. It was able to observe the fine structure of the particle when the virus was stained with phosphotungstic acid or sodium phosphotungstate. Fixing the purified virus particles with 2% neutral formalin resulted in the revelation of a clearly hexagonal or pentagonal image. Purified ICH virus particles keep infectivity and complement fixing and hemagglutinating activities and can be disintegrated by treatment with ether with the liberation of smaller particle, soluble antigen and hemagglutinin. The ultraviolet absorption spectrum of final purified virus particles shows a maximum at 258 mμ and a minimum at 240 mμ

STUDIES ON HEPATITIS CONTAGIOSA CANIS I. : INFECTION EXPERIMENTS ON DOGS WITH TWO STRAINS OF THE VIRUS AND SEROLOGICAL INVESTIGATIONS WITH THE COMPLEMENT-FIXATION TEST

1. By using two strains, "YAMAGUCHI" and "MATSUDA", of H.c.c. which were encountered in Sapporo, serial transmission experiments on puppies aged 14〜90 days were conducted. In case of the "MATSUDA" strain, the fatal infection could be transferred to the 3rd passage, however only non-fatal infection occurred in dogs at the 4th passage. On the other hand, in the "YAMAGUCHI" strain the authors could not bring out any fatal infections. 2. The clinical symptoms of puppies were variable even within the same litter. Fatal infection was found to occur in 28.6% (8/28) in the "MATSUDA" strain but 0% in the "YAMAGUCHI" strain. The total infection rates including fatal, severe, mild or inapparent form were 75% (21/28) with the former and 60% (6/10) with the latter strain. 3. Complement-fixing antibody was developed during the period of 12〜15 days after inoculation. There seems to be no relationship among route, dose, severity of the clinical signs or viral strains examined. 4. In order to ascertain the prevalence of this disease in Japan, a survey on distribution of C.F. antibody among dogs from 4 districts was conducted. One hundred and eighty-six dog serum samples out of 374,nearly 50%, reacted positively. There seems not to be very much difference among districts (44〜57%)

STUDIES ON EQUINE PARATYPHOID VACCINE : III. CLINICAL REACTIONS AND ANTIBODY RESPONSES OF HORSES TO CHROME VACCINE OF SALMONELLA ABORTUS EQUI

1. Intramuscular injection of chrome vaccine in horses was favourable from the viewpoint of clinical reactions and antibody production. 2. Heat-killed vaccine injected subcutaneously caused early local and systemic reaction and its rapid disappearance compared with chrome vaccine. 3. Chrome vaccine and oil chrome vaccine showed high tendency to cause suppuration when they were injected intra- or subcutaneously. 4. Foals generally react more slightly than two-year-old colts. 5. Marked increase of antigenicity was not observed in chrome vaccine. 6. Peanut oil adjuvants without lanoline had no enhancing effect on chrome vaccine. 7. Duration of antibody production in 5〜8.5 months old foals is shorter than that in two-year-old colts