Resistance against Schistosoma mansoni induced by highly irradiated infections: studies on species specificity of immunization and attempts to transfer resistance

Significant levels of resistance against Schistosoma mansoai challenge were developed by mice exposed to highly irradiated (20 krad.) cercariae of the homologous species (53–67%), whereas vaccination with S. bovis, S. haematobiurn or S.japonicuni failed to confer significant levels of resistance (–5–12%), thus confirming the specificity ofthe immunizing procedure. Attempts to transfer resistance to naive recipients by injection of serum and of spleen or lymph node cells from donor mice vaccinated with highly irradiated cercariae were largely unsuccessful. However, significant levels of resistance could be transferred to mice by injection of serum from rabbits exposed to irradiated cercariae. Comparable levels of resistance were conferred by injection of serum at the time of challenge (34–69%) or 5–6 days later (31–56%). Tn contrast, sera from rabbits injected with solubleegg antigen or homogenized cercariae failed to confer protection upon recipient mice. Sera from vaccinated mice, vaccinated rabbits and antigen-injected rabbits all caused cell adherence to skin-transformed schistosomula hut neither the level of adherence nor the serum titre correlated with the ability to confer protection to mice.

LONG ACTING THYROID STIMULATOR (LATS) AND IODO-AMINO ACIDS IN LOCALIZED PRETIBIAL MYXOEDEMA

ABSTRACT Three patients with so-called localized pretibial myxoedema were studied. The serum titre of LATS activity and the contents of iodo-amino acids were determined. One patient who simultaneously developed a diffuse toxic goitre and pretibial myxoedema showed a high titre of LATS. The second patient who developed pretibial myxoedema showed no LATS activity. This patient probably had a recurrence of Graves' disease in a nodular goitre. The third patient who developed pretibial myxoedema a few years after thyroidectomy for diffuse toxic goitre possibly had a low titre of LATS. The serum contents of iodo-amino acids were increased in cases 1 and 2. The analysis was unsuccessful in case 3. The significance of the findings is briefly discussed. It is concluded that the development of pretibial myxoedema is not correlated with the occurrence of LATS.

The transmission of anti- Salmonella agglutinins from the mother to the young in Erinaceus europaea , with some observations on the active immunization of suckiling hedgehogs

The transmission of anti- Salmonella agglutinins from actively immune mothers to their young was studied. Transmission of passive immunity in the hedgehog occurs both before and after birth, but the greater part occurs after birth. Concentration quotients (C. QS) ranging from 1/32 to 1/8 were obtained in five young sampled before suckling. C. QS of 1/2 were obtained in suckling young at 4 to 6 days of age, and in the young of two litters the C. QS were between 1/4 and 1/2 during the first 20 days of lactation. Subsequently the serum titres of the young declined. Uptake of antibody from the milk by the gut occurs during the first 20 days of lactation, and probably continues up to 30 days of age. In none of the young sampled did the serum titre equal that of the mother. The milk titre shortly after birth was 50% of the maternal serum titre and this proportion was maintained throughout the lactation period. Suckling hedgehogs given a single injection of Brucella abortus at from 9 to 21 days of age produced low circulating titres after 6 days, and are thus able to produce specific agglutinins during the period when antibody is being absorbed from the milk.

The selection of antibodies by the gut of the young rat

The young of mother rats which had been immunized against Salmonella pullorum absorbed relatively much less antibody when they suckled during the period shortly after the initial immunization than during the period of hyperimmunity. After hyperimmunization against Brucella abortus both the maternal serum titres attained and the amounts of antibody reaching the young were similar to those of rats given a single immunizing injection of Salmonella pullorum. Antibodies from hyperimmune anti-SaZm. pullorum sera produced in a number of species of rodents and in rabbits, and from hyperimmune anti-Brucella abortus sera produced in rats, guinea-pigs and rabbits, when fed to young rats, were absorbed in amounts which were independent of the species in which the antisera were produced but related to the antigen used. The gut of the young rat was therefore showing a selection between antibodies produced in the same animal to the same antigen, the donor differing only in serum titre and length of the immunization period; and between antibodies produced in the same species to different antigens. The fractionation of antisera and titration of the fractions produced evidence that this selection of antibodies is related to their location in the serum proteins.

The transmission of anti- Brucella agglutinins from the mother to the young in Erinaceus europaea

The transmission of anti- Brucella agglutinins to the young from mothers immunized during pregnancy, and from mothers immunized before and during pregnancy was studied. There is no significant transfer of anti- Brucella agglutinins before birth, and the post-natal transfer of these antibodies is of a very low order. The highest concentration obtained in the sera of suckling young was only 3% of that in the maternal sera. At parturition the titre of the milk is of the same order as that of the maternal serum, but with suckling it declines to about 25% of the maternal serum titre.

Rinderpest Immunity in Calves: II. Active Immunization

Calves which were the progeny of rinderpest-susceptible dams were inoculated with lapinized rinderpest virus when 1 day to 2 months old. Their serological response, as measured by neutralizing antibody titre 21 days later, did not differ from that of adult susceptible cattle.In calves born of rinderpest-immune cows, the serological response to caprinized rinderpest virus depended upon the level of maternally derived antibody. There were two critical levels, one below which all calves produced antibodies (serum titre of 0.7 or less) and another above which no antibody was formed (serum titre of 2.2 or more). Thus all animals aged 8 months or more at the time of inoculation were actively immunized but no calf aged 3 months or less reacted in this manner.The response of calves with maternally derived antibody titres between 0.9 and 2.0 varied. There was a significant inverse relationship between the preinoculation titre and the amount of antibody formed during the following 3 weeks. A similar inverse relationship was shown between the pre-inoculation titre and the rate of production of antibody and its titre 1 year following inoculation.Calves which possessed colostral antibody, and which were actively immunized by caprinized virus inoculation, did not necessarily show the usual clinical reaction. When such animals failed to become actively immunized there was no sensitization of the antibody-forming mechanism, a fact demonstrated by the lack of an anamnestic response to subsequent exposure to rinderpest virus antigen.I owe thanks to many people: to Dr S. E. Piercy, Deputy Director, E.A.V.R.O., for advice and encouragement; to Mr G. R. Scott, Senior Virologist, E.A.V.R.O., for advice and encouragement and, with Mr G. J. Knight, for help in the statistical analysis of the data; to Dr M. H. French lately head of Division and Mr G. Lampkin, Joint Animal Industry Division of E.A.A.F.R.O. and E.A.V.R.O. for facilities for the inoculation of calves from rinderpest-immune dams with rinderpest vaccine; Mr J. M. Nightingale, Sasamua Estate, South Kinangop, and Mr J. Armstrong, Naivasha, for facilities for immunizing calves from rinderpest-susceptible dams; Mr C. S. Rampton, Mr N. Kerani and Mr F. Mwithiga for technical assistance.This and the previous paper (see p. 427) are published by permission of the Director, East African Veterinary Research Organization.

The Active Immunization of Guinea-Pigs Passively Immunized with Homologous Antitoxic Serum

SummaryGroups of guinea-pigs were passively immunized against diphtheria toxin with homologous antitoxic serum so that their sera contained, at the start of the experiment, 1·0, 0·1, 0·01 or 0·001 unit/ml, respectively. They were then actively immunized with one, or two spaced, injections of 0·1 Lf of A.D.F. Two control groups were included, one passively immunized only and the other actively immunized only.Passively produced serum titres of 0·01 and 0·001 unit/ml. did not interfere with active immunization in any demonstrable way.A titre of 0·1 unit/ml. did interfere with active immunization, markedly 4 weeks after the primary, slightly 2 weeks after the secondary, and markedly 14 weeks after the secondary, stimulus.A titre of 1·0 unit/ml. interfered with active immunization, markedly 4 weeks after the primary, and 2 and 14 weeks after the secondary, stimulus. This titre, however, did not completely annul the effect of the primary stimulus. The highest observed serum titre was obtained at the 32nd, instead of at the 4th week, as in the guinea-pigs actively immunized only.In large measure the results confirm those of Barr and her colleagues who found that, in human babies, an initial ‘passive’ titre of 0·04 unit/ml. serum did not interfere with active immunization, whereas a titre of 0·1 unit/ml, led to unsatisfactory immunization.

The origin of urinary antibodies

1. Antibodies to the flagellar antigens of salmonellae are frequently present in the urine of Egyptians.2. In many individuals, who are not urinary carriers but have schistosomiasis and have received T.A.B. vaccine, these urinary antibodies are derived from the plasma due to exudation or bleeding into the urinary tract.3. In urinary enteric carriers, the urinary antibodies are due, at least in part, to the local production or release of antibodies within the urinary tract, as shown by the ratios of urine titre to serum titre with different H suspensions.4. The production of antibodies within the urinary tract is considered to be an example of production or liberation of antibody by cells at, or close to, the site of infection.

Some antigenic properties of mammalian spermatozoa

Methods of testing sera for precipitins against seminal proteins, and for spermatozoal agglutinins are described. The influence of various factors on agglutination of rabbit and guinea-pig spermatozoa in hanging drop preparations has been investigated. In diluted normal sera agglutination of spermatozoa by their tails occurred rarely, and then only in low serum dilutions. In the sera of immunized animals tail agglutination commenced within 10 sec., and titres could be read after 20 min. Altering the pH of the diluent below 7·0, or above 8·1, reduced the serum titres. Washed spermatozoa from semen or from the epididymis were agglutinated to higher serum titres than unwashed spermatozoa from the same specimens. A fourfold increase in the con­centration of unwashed rabbit spermatozoa, and an eightfold increase in the concentration of washed rabbit spermatozoa halved the serum titre. Additions of complement did not, in the proportions used, alter the agglutination titres of antisera or the motility of the spermatozoa. The agglutination of rabbit spermatozoa is inhibited by fluid from the vagina. It can be reversed by mechanical means, or by addition of fresh spermatozoa in excess. With guinea-pig spermatozoa disagglutination has been achieved by mechanical methods only. Mixed agglutinates of spermatozoa of different species can be produced by antisera which agglutinate them separately.