Passively and actively acquired antibodies for Trichomonas foetus in very young calves

Effects of an immune challenge on the thermal preferences of adult and newborn Liolaemus lizards from Patagonia, Argentina

Body temperature has relevant effects on the immune response. Here, we characterized the thermal biology and health condition of the viviparous lizard Liolaemus kingii from Patagonia (Argentina), by studying field body temperatures, presence of injuries or ectoparasites, body condition (BC), and individual immune response capacity with the phytohemagglutinin (PHA) skin-swelling assay. In addition, we analyzed the effects of injections of a bacterial endotoxin (lipopolysaccharide; LPS) on the preferred temperature (Tp) and BC of adult males and newborns. The PHA treatment caused detectable thickening at 2 and 20 hours post-assay in males, indicating a significant immune response related to an increase in cellular activity. LPS-challenged lizards thermoregulated accurately and at stable body temperatures within the 50% interquartile of Tp (Tset) over the 72-hour period while the control group showed a more variable and lower Tp. Exposure to LPS negatively affected the BC of newborns, whereas it did not affect the BC of adult males. LPS challenges, used as a proxy of pathogen exposures to study lizard behavioral thermoregulation, constitute a practical approach to assess the immunological constraints lizards from high-latitude regions may face due to global warming and anthropogenic disturbances.

Acknowledging extraordinary women in the history of medical entomology

Throughout history, women have been actively involved in the advancement of science, while struggling to overcome challenges to participate and a lack of recognition. Prior to 1950, most women were not included in the lists of "classical" descriptions of the iconic scientific figures nor included in the most relevant historical accounts. Since the second half of the twentieth century, great efforts have been made to recognize the contributions of women to the advancement of science, especially since formal scientific careers have been dominated by men, with limited (or no) access to women. Despite these challenging social, political and cultural contexts, many women have succeeded in making significant advancements, and their contributions are now being acknowledged. Such efforts have led to the publication of recent reviews and compilations on outstanding women in biological sciences. The field of medical entomology is inherently interdisciplinary, focusing on insects and other arthropods that affect human health, with input primarily from the biological and medical sciences and a strong public health perspective. Several reviews and book chapters describing the history of medical entomology have been published over the decades, but few women are mentioned in these publications, even though many women have contributed to this field. Much of the information on these women is currently scattered throughout the published literature and historical records on a wide range of topics, including activism, virology, vector control and even acarology. Considering that there is no single available compilation of women contributors in the history of medical entomology, this review aims to provide a list of 22 women and their contributions to this field. The list includes women from diverse backgrounds, born in the late 1800s and before 1950, who directly impacted medical entomology in various ways and in different regions of the world. This compilation is far from exhaustive, but it aims to identify role models and examples of extraordinary women to motivate the evolving future of this field.

Effects of the ingestion of whole colostrum or cell-free colostrum on the capacity of leukocytes in newborn calves to stimulate or respond in one-way mixed leukocyte cultures

OBJECTIVE

To evaluate effects of colostral cells on the ability of neonatal leukocytes to respond in a mixed leukocyte response (MLR) as a means of evaluating specific immune responsiveness.

ANIMALS

10 Holstein calves, their respective dams, and 10 unrelated adult Holstein cows.

PROCEDURE

Soon after birth, their calves were fed maternal whole colostrum or colostrum after cells were removed by centrifugation. Responses for leukocytes obtained from calves during the first 5 weeks after birth, their dams, and unrelated cows were measured by use of 1-way MLR as an indicator of immune development. An internal control treatment, proliferation of lymphocytes stimulated with Staphylococcus enterotoxin B (SEB), was also measured.

RESULTS

Transfer of colostral leukocytes had a significant effect on the MLR and SEB-induced response in calves. Calves receiving whole colostrum had enhanced responses to maternal and unrelated leukocytes 24 hours after ingestion of colostrum. These responses decreased quickly, indicating direct modulation of the neonatal immune response. Calves receiving whole colostrum effectively stimulated the MLR by 24 hours after ingestion of colostrum. In contrast, calves receiving acellular colostrum did not effectively stimulate the MLR until 2 to 3 weeks after birth.

CONCLUSIONS AND CLINICAL RELEVANCE

Ingestion of maternal colostral leukocytes immediately after birth stimulates development of the neonatal immune system. These maternal leukocytes enhance development of antigen-presenting capacity as indicated by their ability to stimulate the MLR and SEB response. The influence of ingested maternal cells on neonatal immunity was also indicated by a reduction in reactivity of neonatal cells to maternal alloantigens.

Immunological unresponsiveness in rabbits produced by neonatal injection of defined antigens

The phenomenon of immunological unresponsiveness induced in the neonatal rabbit by a single injection of a defined protein antigen, has been characterized semiquantitatively, and studies bearing upon the mechanism of such unresponsiveness have been presented. A single intraperitoneal injection at birth of 10 to 100 mg. BSA, HGG, ovalbumin, or a human macroglobulin, or an oral feeding of 100 mg. BSA, induced a state of unresponsiveness lasting at least 90 to 120 days. 100 mg. BSA given from birth to 17 days of age, but not later, produced unresponsiveness of 90 to 120 days' duration. Data are presented which show that the duration of unresponsiveness is finite and related to the amount of antigen given at birth, and that it may be indefinitely prolonged by repeated injections of antigen. Disappearance of injected antigen in the unresponsive animal was exponential with time, with no accelerated or immune phase. Administration of the antigen in adjuvants resulted in significant shortening of the duration of unresponsiveness. The transfer of immune cells to the unresponsive host while resulting in vicarious antibody formation, did not affect the underlying unresponsive state. Negative results of attempts to produce unresponsiveness to a variety of bacterial antigens are presented. The implications of the data are discussed, particularly in reference to the other experimental models of immunological tolerance, and to the various theories of acquired immunity. It is clear that any satisfactory theoretical explanation of acquired immunity will have to account simultaneously for the phenomena of immune tolerance.

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.

Inhibition of tuberculin skin hypersensitivity in guinea pigs by injection of tuberculin and intact tubercle bacilli during fetal life

Female guinea pigs were subjected to laparotomy at different stages of pregnancy, and their fetuses injected through the uterine walls with one of the following preparations: Old Tuberculin, tubercle bacilli of the BCG strain killed by heat or exposure to phenol, and living BCG. A large number of the animals injected in utero with Old Tuberculin failed to develop skin hypersensitivity to P.P.D. following vaccination with 200 or 800 γ phenol-killed tubercle bacilli (BCG) in early adulthood. Normal control animals were sensitized by vaccination with such quantities of phenolized BCG. The failure of animals which had been injected with Old Tuberculin in fetal life to respond hypersensitively to P.P.D. after adult vaccination with tubercle bacilli is ascribed to their acquisition of a state of immunological tolerance to tuberculoprotein (tuberculin tolerance). Fetal injection with killed BCG conferred a state of tolerance on a few of the animals, and rendered others tuberculin-sensitive. Fetal injection with living BCG sensitized most of the animals to tuberculin, even when fetal exposure was as early as 46 days before birth, and induced tolerance in none. Fetuses of the same litter, injected simultaneously with identical inocula, often responded differently, some becoming tolerant to tuberculin, others developing hypersensitivity, and still others remaining immunologically unaffected, becoming neither sensitive nor tolerant. The state of tuberculin tolerance induced in these experiments was limited. When tolerant animals were revaccinated with living BCG several weeks after vaccination with phenol-killed bacilli, they developed as high a degree of tuberculin skin sensitivity as the originally non-tolerant animals.

The development of the immune response. Studies on the agglutinin response to Salmonella flagellar antigens in the newborn rabbit

By intensive stimulation with large amounts of Salmonella flagellar antigen, newborn rabbits were induced to form high titer flagellar agglutinins usually by the 7th to 10th day of life. Characterization of the agglutinins at various times during the first 30 days of life revealed that the earliest antibody which appeared was a gamma-1 macroglobulin, and that 7S gamma-2 globulins did not appear until the 4th or 5th week of life. In contrast, the adult animals produced macroglobulin antibodies for only 3 to 5 days before the lower molecular weight variety appeared. The infant macroglobulin appears to be similar in all respects to adult macroglobulin antibodies. These data are interpreted to indicate that the newborn and adult rabbit differ in their response to this type of stimulus not in timing of macroglobulin antibody production, but chiefly in the prolonged interval, which precedes the development of the capacity for the 7S type response in the newborn animal.

Ultracentrifugal and electrophoretic studies on neonatal calf sera and maternal colostrum

1. Neonatal serum proteins and those of maternal colostrum have been examined in the Spinco analytical ultracentrifuge and the Perkin-Elmer electrophoresis apparatus. To facilitate correlations between the two types of result, certain protein fractions have been prepared electrophoretically and examined in the ultracentrifuge.

2. The electrophoretically distinguishable components of precolostral serum, albumin, α and β globulin and traces of γ globulin sedimented mainly as a single boundary which showed evidence of a slower component (probably fetuin) with a sedimentation constant of about 3S. A small proportion of a macroglobulin component (S020 ≅ 16S), associated with the α globulin, was also present. In conformity with the very low γ globulin, there was a complete lack of globulin with S020 ≅ 6·5–7·0S. The β globulin and the bulk of the α globulin sedimented closely with albumin, whose sedimentation constant in an electrophoretically isolated fraction was somewhat lower than normal, probably as a result of α-globulin contamination.

3. The electrophoretic and ultracentrifuge analysis of postcolostral calf serum showed evidence of passive absorption from the maternal colostrum of immune lactoglobulin. There was a rise in the concentration of total serum protein of which up to 51·6% was immune lactoglobulin, of sedimentation constant 6–6·5S. No such component occurs in precolostral sera. The electrophoretic and ultracen-trifugal characteristics of this globulin were not significantly altered as the result of absorption. The acquisition of immune lactoglobulin was accompanied by a simultaneous fall in serum albumin concentration.

4. Examination of colostrum, rennin-produced colostral whey, and of electrophoretic fractions prepared from colostrum showed the presence of a small proportion of a macroglobulin (S020 ≅ 18S), a well-defined immune lactoglobulin of S020 ≅ 6·4S and electrophoretic properties in the γ-range, and a group of electrophoretically more mobile components with sedimentation constants ranging downwards from 3S.

5. Electrophoretically prepared fractions from the serum of a deprived calf 27 days old showed sedimentation properties in conformity with the results on precolostral sera, with the macroglobulin component being again associated with α globulin. The remainder of α and β globulin sedimented alongside albumin and the additional γ-globulin component in a single boundary of S020 ≅ 6·5–7S.

6. The concentration of autogenous γ globulin developed by calves which had been deprived of colostrum increased with time and was generally in fair agreement with that of the 6·5–7S component.

The authors wish to thank Sir Alan Drury, F.R.S., for his interest and encouragement during the course of this work, Mr N. Buttress, Mr D. Hardman and Miss J. Mallon for technical assistance and Mr J. Clark for assistance in the care and handling of the calves.

IMMUNOLOGIC TOLERANCE AFTER SPECIFIC IMMUNIZATION

Specific immunologic tolerance to bovine serum albumin (BSA) was induced in approximately one-half of the rabbits that had been primarily immunized and were prepared for a secondary antibody response to BSA. The state of tolerance lasted for several months in the majority of rabbits and was not easily terminated by immunization with human serum albumin followed by BSA.

Plasmodium berghei adoptive transfer and immunosuppression of immunity in allogenic neonates

Outbred female rats were hyperimmunized with Plasmodium berghei and mated to produce progeny. Spleen cells from the immunized rats and from normal control mothers were adoptively transferred to their 48 hr old neonates. Some neonates from immune mothers were fostered to normal mothers and vice versa. Weanling rats were challenged 35 days after birth with Plasmodium berghei; immune and normal litters which had not received cells were also challenged at the same time. Rats which had received immune spleen cells from their mothers but were fostered on to non-immune mothers showed significantly lower parasitaemias and higher fluorescent antibody titres than any other combination of cell transfer and maternal milk. GVH reaction was minimal. These results suggest that the immune response to P. berghei was suppressed in the presence of passively transferred maternal antibody.

Experimental infection of newborn calves with coccidia and reinfection after weaning

Four newborn Hereford calves were orally inoculated five times with 100 sporulated oocysts of coccidia, predominantly Eimeria zurnii. Each calf was kept isolated with its dam until weaned at the age of 13 weeks. Three other newborn calves were similarly isolated but not experimentally infected. The calves were then challenged with 300,000 sporulated oocysts at the age of five, seven and nine months. The previously unexposed calves developed marked clinical coccidiosis after the first challenge, but resisted the second and third challenge. The neonatally exposed calves were susceptible to infection at the first challenge as well as to the next two challenges at seven and nine months of age, but the clinical signs following the last two challenges were milder than those of the first challenge. These findings suggest that under conditions where calves become infected with coccidia when very young, such calves may, by shedding oocysts in large numbers for long periods, be a continuing source of coccidial infections to other animals.

Induction of immunological tolerance in rats to Nippostrongylus brasiliensis infection

A successful attempt was made to induce immunological tolerance to N. brasiliensis in laboratory rats by exposing them to larval infections before the age of immunological maturity.

The adult capacity of rats to eliminate a primary infection in 3 weeks and to acquire resistance to reinfection was developed by 5 weeks of age. On the other hand, primary infections of 250–660 larvae, originating before 4 weeks of age, survived in 61 of 83 rats up to 10 weeks. These rats were not resistant to challenge at 5 or 7 weeks of age, nor did the challenge infection undergo immune elimination. Such tolerance was evident even in rats whose primary worm burden was chemically abbreviated prior to challenge.

It was not always possible to distinguish between tolerant and immune animals on the basis of egg output patterns. Suppression of egg output occurred even in tolerant rats harbouring relatively stable female populations.

For immunological experiments on N. brasiliensis infection in rats, the determination of a ‘take ratio’ is advocated: (20 day take/10 day take) × 100. This ratio eliminates the error inherent in variability of takes and renders comparable the results of different experiments.

The work was carried out in 1965 during tenure by one of us (T.K.) of an Exchange Scholarship under the British–Hungarian Cultural Agreement. Supervision by Professor W. Mulligan and the co-operation of colleagues in the Wellcome Laboratories are gratefully acknowledged.

The effect of pre- and neonatally injected diphtheria toxoid on the homologous responsiveness of young guinea pigs. A preliminary report

A number of guinea pigs injected prenatally with diphtheria toxoid were found to be incapable of making flocculating antibodies to the antigen after immunization in early adulthood. Several of these animals showed an exaggerated susceptibility to diphtheria toxin.

Development of immunity to tuberculosis in adult mice injected with tubercle bacilli during foetal life

The methods successfully used to induce immunological tolerance in mice to a variety of antigens were applied to studies on mycobacterial antigens (whole tubercle bacilli). Mice were injected with approximately 5×10⁵ living attenuated (BCG) or heat-killed virulent (H₃₇Rv) tubercle bacilli on the 15th, 16th or 17th day of foetal life. Acid-fast bacilli were found in the lungs, spleens and livers of these mice after birth. Such mice subsequently developed normally and were not more susceptible to BCG than mice primarily infected in adult life.

The immunological state of the mice exposed to mycobacteria in utero was determined by challenging 5 to 6 weeks after birth with either virulent or attenuated tubercle bacilli. These tests showed that an intra-embryonic injection of mycobacteria resulted in protective immunity and not tolerance. Furthermore, the mice also showed delayed-type hypersensitivity to mycobacteria.

These results are discussed in relation to the ability of other antigens to induce immunological tolerance in mice and to the response of other animal species to mycobacteria.

Partial immunological paralysis to Trichomonas foetus antigen in calves

The intramuscular injection of large amounts, 2–3 g., of Trichomonas foetus crude antigen into five young calves during the first 3 weeks of life produced no antibody.

When the animals were tested with the standard challenge at intervals of several months they responded feebly, showing a definitely impaired capacity to produce antibody, when compared with the response of normal animals.

The ages of the animals still showing this partial paralysis ranged from 1 year and 5 months to 2 years and 2 months.

Acquired immune tolerance to human albumin and the response to subsequent injections of diazo human albumin

Images

Electrophoretic and immunological studies on sera from calves from birth to weaning. II. Electrophoretic and serological studies with special reference to the normal and induced agglutinins to Trichomonas foetus

Images