Antibody-positive Animals Research Articles

Natural Transmission of Gibbon Leukemia Virus<xref ref-type="fn" rid="FN1">2</xref>

Gibbon leukemia virus can infect prenatal gibbons through in utero infection or postnatal gibbons through contact transmission. The transmission of infectious virus was from viremic gibbons and not from uninfected or antibody-positive animals. The two modes of transmission could be distinguished by the amount of proviral DNA integrated into the muscle tissue of viremic gibbons. Muscle of gibbons infected postnatally had little or no proviral DNA, whereas gibbons infected prenatally had a large quantity of proviral DNA.

Long term surveys on Tyzzer's disease in three rat breeder colonies (author's transl)

Retired rats of SD strain from three breeder colonies (A, B and C) were monthly monitored for CF antibody to Tyzzer's organism for 2 to 6 years. In colony A, antibody-positive rats were found at frequencies ranging from 5 tp 100% with a single peak during about one year without any detectable signs of apparent disease. However, in colony B, in spite of the outbreak of the disease, antibody-positive animals were only sporadically detected during about 4 years after the outbreak. Thereafter, in this colony, the antibody was not demonstrated in all animals examined for 2 years, and susceptibility to the disease of 3-week-old rats was the same as that of ones from one-infected colony. Cortisone test did not suggest the infection. In colony C, no antibody-positive rats were detected for 3 years.

TRANSPLANTATION OF AUTOIMMUNE POTENTIAL

Lethally irradiated (850 rads) DBA/2 mice which had been transplanted 10 months previously with 2 times 10-6 bone marrow cells from 3-week-old donors of the H-2-histocompatible NZB, BALB/c and DBA/2 strains were examined for manifestations of autoimmune disease. Also studied were lethally irradiated (950 rads) NZB mice grafted with NZB marrow. Strongly positive antinuclear antibody responses were present in all NZB and DBA/2 recipients of NZB marrow, but absent in DBA/2 mice grafted with BALB/c and DBA/2 marrow cells. The antinuclear antibody-positive animals had glomerulonephritis with the deposition of globulin in or along the basement membranes. These observations support the view that the potential for autoantibody formation and subsequent autoimmune disease development is inherent to the NZB hemopoietic stem cell and their progeny.

高濃度日本脳炎不活化ワクチン1回接種による豚の死産予防試験

It is possible to prevent stillbirth in swine caused by infection with Japanese encephalitis virus by inoculating sows with 2 or 3 10-ml doses or 3 5-ml doses of the existing high-potency Japanese encephalitis vaccine. This trial was carried out in Shizuoka Prefecture in 1969 to find a possibility of reducing the amount and the number of doses of vaccine for inoculation. In it, a vaccine was prepared tentatively in such manner as to contain tissues at a concentration about 3 times as high as that of the existing high-potency vaccine.A total of 119 nulliparous swine were divided into 5 groups, A to E. Group A of 27 antibody-negative animals was inoculated with two 10-ml doses of the existing high-potency vaccine, and group B of 29 animals with a single 10-ml dose of the tentatively prepared high-concentration vaccine. Group C of 24 animals was set up as uninoculated control group, and group D of 28 antibody-positive animals as another control group. Group E of 11 antibodypositive animals was inoculated with a single 10-ml dose of the high-potency vaccine. In caeh group, antibody titers were determined 3 weeks after inoculation and immediately after parturition, and the results of delivery recorded.After inoculation 100 and 96 % of the animals of groups A and B, respectively, turned to be positive for antibodies, neutralizing and hemagglutinationinhibiting.The average number of young normally delivered per litter was 8.3 (in 16 sows examined) in group A, 8.2 (in 17 sows) in group B, 5.3 (in 14 sows) in group C, 9.7 (in 15 sows) in group D, and 9.7 (in 7 sows) in group E. There was a marked difference in this number between the inoculated groups (A and B) and the uninoculated control groups, but no difference between groups A and B.Group B presented no inferior results of delivery but relatively low rate of antibody production and average antibody titer, as compared with group A.

POWASSAN VIRUS: FIELD INVESTIGATIONS DURING THE SUMMER OF 1963.

Summary During summer 1963, examination of sera from 496 forest mammals collected within 30 miles of North Bay, Ontario, Canada, revealed the presence of neutralizing antibody to Powassan virus in 22 of 194 red squirrels, 16 of 29 woodchucks, 13 of 34 porcupines, none of 107 snowshoe hares and 7 of 132 other mammals. Ixodes sp. ticks were removed from 54 squirrels, woodchucks and porcupines, 12 of whose sera neutralized Powassan virus. The prevalence of antibody-positive animals was highest during May and September, and these animals were captured almost exclusively in small forested areas of Nipissing, South Himsworth and Bonfield Townships. No virus was isolated from any ticks removed from 59 animals apart from snowshoe hares, or from 325 animal blood clots, by inoculation of suckling mice. One strain of Silverwater virus was isolated from Haemaphysalis leporis-palustris ticks taken from a snowshoe hare in North Himsworth Township on 5th May 1963, and complement-fixing antibody to Silverwater virus was detected in 21 of 107 showshoe hare sera, obtained principally in that Township. Antibody to California encephalitis virus was detected both by complement-fixation and neutralization tests in sera from 9 of 107 snowshoe hares.