Some biological effects of IgM anti-Rh (D)

Twelve previously uninjected D-negative subjects were given 1 ml of D-positive cells together with 30–90 μg IgM anti-D intravenously; about 50 per cent of the cells were cleared within 48 hours, and the remainder were cleared far more slowly; at 6 months two of the subjects had formed anti-D. All subjects were then given a second injection of D-positive red cells but without passive antibody; two subjects without demonstrable anti-D at the time of this injection showed accelerated clearance within the first week and developed anti-D within 6 weeks. The proportion of subjects forming anti-D (four out of twelve) was not significantly different from that found in a previous series injected with red cells alone and it was concluded that these doses of IgM anti-D had failed to suppress immunization.

It has previously been proposed that the proper criterion for judging augmentation of immune responses in D-negative subjects is not the proportion of subjects becoming immunized but rather the characteristics of the response in subjects capable of responding. In the present series no definite evidence was obtained that antibody formation was brisker or greater in those subjects who received passive IgM antibody together with their first injection of D-positive red cells.

Survival of Vibrio parahaemolyticus in fish homogenate during storage at low temperatures

Fish homogenate inoculated with Japanese strains of Vibrio parahaemolyticus were either stored at 0.6 C or frozen and stored at -18 and -34 C. Greater survival of the organisms was obtained at 0.6 C than at the lower temperatures.

Standardization of human diploid fibroblast cultivation: centrifugation procedure

The effect of varying centrifugal forces on the growth rate, longevity, and adsorption on glass of human embryonic diploid lung fibroblasts was studied. Cells centrifuged at 120, 500, or 1,500 x g at each passage had similar growth rates but their longevity decreased slightly with increasing force. These forces had no influence on the proportion of cells attaching to the glass. When the material in the first supernatant was recentrifuged at 2,000 x g for 30 min and added to the cells precipitated in the first centrifugation, the longevity of these cells was increased by several cell divisions. Cells which were not centrifuged but added directly from the cell suspension in trypsin to the new culture grew at a slightly slower rate than the centrifuged cells and became senescent at an earlier time. However, the noncentrifuged cells adsorbed to glass better than those centrifuged.

Autoimmune haemolytic anaemias. IV. Biochemical studies of red cells from patients with autoimmune haemolytic anaemia with incomplete warm autoantibodies

The most noticeable biochemical abnormality of red cells of patients with autoimmune haemolytic anaemia with warm autoantibodies is the increased osmotic fragility of the red cells. This appeared to be most pronounced in patients with incomplete IgG warm autoantibodies and to be significantly correlated with the ⁵¹Cr T_½ of the patients' red cells. It appeared to be a disturbance of the cells which slowly increased with time. It only occurs in vivo and the reaction of the cell with the autoantibodies is necessary. Possibly, it is caused by damage done to the sensitized red cells by the RES. It is accompanied by an increased K⁺ efflux of the red cells. Interaction of red cells and antibody in vitro has no effect. A number of other biochemical abnormalities, such as increased enzyme activities, increased glycolysis and ATP breakdown, also correlated with the ⁵¹Cr T_½ are probably the result of the lower mean cell age of the red cells.

Studies of skin fibroblasts from 10 families with HGPRT deficiency, with reference in X-chromosomal inactivation

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Drug sensitivity and mutability to drug resistance associated with the presence of an R factor

Studies on the growth kinetics of R+and R−cultures ofEscherichia coliin the presence of nalidixic acid (NA), acriflavine (AF) and kanamycin (Kan) showed that each drug caused a decline in viability of both R+and R−cells for several hours. During further incubation the viability rose rapidly for the R+cultures, but either rose less rapidly (AF and Kan) or continued to decline (NA) for R−cultures. Distribution curves of the resistances of individual clones of R+and R−bacteria to atabrine, NA, AF and Kan suggested that the presence of an R factor in the host bacterium increased its mutation rate to resistance to these drugs: this would account for the more rapid growth rate of R+cells during the latter stages of incubation in their presence. The mutations causing increased resistance to NA and to Kan were located in the bacterial chromosome and not in theRfactor.

In vitro reactivity of human lymphocytes in chronic uraemia: analysis and interpretation

Altered cellular immunity complicating chronic uraemia includes lymphocytopenia, thymic atrophy, impaired allograft rejection and delayed hypersensitivity in skin tests, diminished appearances of lymphocytes on skin windows, and shortened in vitro survival of uraemic lymphocytes. Studies were undertaken to further characterize these lymphocyte defects.

Lymphocytes separated from peripheral blood of twenty-four uraemic patients were compared with those from fifty-one normal persons in their rates of RNA and DNA synthesis in both PHA-stimulated and unstimulated cultures, as determined by incorporation of radiolabelled precursors. Synthesis, expressed as absolute incorporation/10⁶ viable lymphocytes, was accelerated in the majority of both stimulated and unstimulated uraemic cultures. Serial studies over several months of twenty-five uraemic patients (fifteen maintained by haemodialysis, ten by renal allotransplantation), compared with nineteen normal controls, showed these differences to be consistent and persistent. While normal lymphocytes exhibited stability, uraemic cells fluctuated widely in their serial synthesis rates. In 25% of such cultures, unstimulated synthesis exceeded that induced by PHA. Increased synthesis without PHA, reflecting enhanced spontaneous blastogenesis, is compatible with decreased survival, numbers, and functional capacity of uraemic lymphocytes.

Reports by others of diminished PHA-responsiveness of uraemic lymphocytes are based upon whole-culture incorporation and/or expressed as ratios between stimulated and unstimulated cultures. Both shortened survival and accelerated spontaneous nucleic acid synthesis by uraemic lymphocytes cause such ratios to be misleadingly low. Such factors as cell numbers and viability at harvest, counting efficiency, and culture sterility are essential to avoid misinterpretations of such data based on incorporation of radiolabelled precursors to the nucleic acids.

The mediator of cellular immunity. I. The life-span and circulation dynamics of the immunologically committed lymphocyte

Thoracic duct cells from rats which have survived an infection with Listeria monocytogenes can confer a high level of antimicrobial resistance upon normal recipients. The cells which confer protection appear in the thoracic duct during the 1st wk of the immunizing infection, at a time when newly formed lymphocytes are being added to the lymph in substantially increased numbers. The protective cells differ in at least two respects from the majority of small lymphocytes in central lymph: they have a rapid turnover rate and a short life-span in the circulation. Evidence was also obtained that lymphopoiesis affecting the long-lived small lymphocyte, which belongs to the recirculating pool, is not increased during an acute Listeria infection.

Life span of lymphocytes within intestinal epithelium, Peyer's patch epithelium, epidermis, and liver of mice

The new concept of first level and second level lymphatic organs, and the fact that all first level lymphatic organs defined so far are lymphoepithelial, justifies a new close look at all types of lymphoepithelial relationships. In this investigation the life span of lymphocytes within different epithelia of mice have been studied with the aid of continuous labelling with H₃-thymidine and subsequent autoradiography. The majority of the lymphocytes within the jejunal epithelium seems to be short-lived. About half of the lymphocytes within the epithelium covering Peyer’s patches and in epidermis also seem to be short-lived, while the other half is long-lived. Most of the liver lymphocytes seem to be long-lived, as are the blood lymphocytes. The results are discussed in the light of other recent findings about lymphocytes within epithelia, which we have called theliolymphocytes.

Potassium binding, growth, and survival of an extremely halophilic bacterium

The potassium content of Halobacterium halobium was studied in media in which the K+ was growth-limiting and in media containing excess K+. In BSM medium (76.5 μg/ml K+) cells grew until all K+ was cell bound. In BSMK medium (1.1 mg/ml K+) cells grew more abundantly; about one-third of the available K+ became cell-bound. Adding glucose or vitamins to BSMK medium stimulated growth and could stimulate K+ binding. However, rapid death in the presence of vitamins reduced the potassium-binding ability of most cultures. Living cells bound very large amounts of K+. After growth stopped in BSM medium they contained about 0.4 g K+ per gram protein; that is, about 30% of the cell's dry weight consisted of K+. This is probably the lowest K+ concentration supporting life of these cells. In BSMK medium, and in the BSM medium in the early stages of growth before all K+ was cell-bound, considerably higher levels of K+ were reached. Altering the pH or the NaCl concentration of the medium within the limits that still permitted growth did not affect the cells' K+ contents.K+ was released when cells in culture died. Non-growing cells incubated at 37 °C in salts solutions without K+ or any energy source lived for up to 3 days, and with K+ for at least 7 days. Their K+ contents remained constant until they died, and then fell. If Mg2+ was omitted from the salts solution cells died more rapidly than in the absence of K+. Dead cells did not lyse or release protein into the external medium.