Antigens in immunity. XVI. A light and electron microscope study of antigen localization in the rat spleen

This paper describes the ultrastructural location of labelled antigens and carbon in the spleens of rats from 4 minutes to 5 days after injection. Particular attention was focused on the sites of deposition 4 minutes after intra-arterial injection of microgram quantities of ¹²⁵I-labelled Salmonella flagellar antigens, crayfish haemocyanin and BSA, using colloidal carbon for comparison. The combination of radioautography with both light and electron microscopy showed the importance of antigen binding by lymphocytes in the marginal zone of the spleen. Macrophage sequestration of antigens was not prominent in the spleen, although it occurred in the liver with the flagellar antigens and haemocyanin.

In the spleen marginal zone, avid antigen-binding cells were found in situ 4 minutes after the injection of labelled haemocyanin. These appear to be the counterpart in vivo of antigen-binding lymphocytes prepared in vitro. Such cells also occurred infrequently after the injection of labelled polymerized flagellin, but were not found with either BSA or carbon.

The apparent movement of flagellar antigen from the marginal zone to the white pulp between 1 and 2 hours after injection was seen to involve lymphocyte-associated antigen. The follicular antigen localization occurring from 1 day onwards after injection was on the dendritic reticular cells of germinal centres, as has been described in lymph nodes after subcutaneous injection.

Carbon particles were rapidly sequestered in macrophages of the spleen and liver, although some particles were found between cells in the marginal zone for as long as 2 hours after injection. By 2 and 5 days, however, all the carbon was in phagocytes, even in the white pulp. Differences between the localization of antigens and carbon were clear, even in the ultrastructural sites of their location in tingible body macrophages of germinal centres.

The unexpected emphasis of lymphocyte association with labelled antigens in the spleen marginal zone has allowed a revison of the mechanism previously proposed for the movement of antigens within the microenvironments of the spleen.

Chlorophyll Derivatives in Middle Eocene Sediments

Chloroform extracts of middle Eocene brown coal were made; the chlorophyll derivatives obtained were separated chromatographically. The visible light spectrum, chromatographic behavior, HCl number, infrared spectrum, and mass spectrum of one of the pigments extracted is indicative of methyl pheophorbide a. This is the oldest occurrence of fossil phorbins reported.

Subpopulations of rat and mouse thoracic duct small lymphocytes in the Salmonella flagellar antigen system

The purpose of the present experiments was to determine whether populations of lymphocytes from mouse or rat thoracic duct lymph deprived of the larger, dividing cells (large and medium lymphocytes) could still transfer adequate primary or secondary adoptive immune responses using syngeneic irradiated hosts. The transfer system used involved the antigen polymerized flagellin from Salmonella adelaide and assay of anti-H antibody levels in the recipients. Two methods of preparation of `small lymphocytes' were used, namely the glass bead column filtration method of Shortman and the agitated culture method of Gowans and Uhr (1966). Both of these yield lymphocyte fractions essentially free of dividing cells.

Unfractionated thoracic duct lymphocytes gave satisfactory adoptive immune responses in both species, primed cells being more effective than normal cells.

In both species and for both primary and secondary immune responses, the Shortman-column fractionated small lymphocytes (col-SL) were grossly impaired in their capacity to transfer adoptive responses. In contrast, the Gowans-type post-incubation small lymphocytes (inc-SL) gave rather better adoptive immune responses. Gowans and Uhr (1966) had found some enhancement of reactivity of inc-SL in comparison with normal lymph cells in another transfer system. We, however, found a mild impairment with unstimulated mouse and rat inc-SL and primed rat inc-SL and a slightly more marked impairment with primed mouse inc-SL.

We have confirmed the finding of Gowans and Uhr (1966) that lymphocyte populations free of dividing cells can mount an adoptive antibody response, showing that a proportion, at least, of the antigen-reactive cells can be described as `small lymphocytes'. The study also revealed the functional heterogeneity of morphologically similar lymphocytes, in that col-SL, morphologically the same as inc-SL, are functionally quite different; they appear to contain very few antigen-reactive cells. In the Salmonella system, therefore, the antigen-reactive thoracic duct cells can be described as lymphocytes which are fairly resistant to agitated culture but which fail to pass through Shortman columns.

Anticipated responses to short-term sensory deprivation

21 Ss were initially tested for discomfort (Somatic Symptom Check List) and anxiety (Affect Adjective Check List) and then viewed a sensory deprivation (SD) Laboratory and given standard SD instructions. Subsequent to viewing the laboratory, Ss were asked to complete the anxiety and discomfort scales as if they had actually undergone 3 hr. of SD. As hypothesized, anticipation scores on scales were significantly higher for both sexes following exposure to the SD laboratory. on the anxiety scales anticipation scores by females were significantly higher than those of males. Data were then compared with scores previously obtained from Ss who had actually undergone the experience. Females anticipated significantly greater anxiety to an SD experience than females who had actually undergone the experience. These results support the general hypothesis that Ss anticipate anxiety and discomfort from an isolation experience.

Psychomotor performance and prognosis of chronic mental patients: an extension of the work of Brooks and Weaver

Previous work dealing with the prediction of successful candidates for psychiatric rehabilitation was extended. 67 chronically ill patients who were hospitalized either at the time of the study or previously were tested on a series of psychomotor tests utilizing an apparatus introduced by Brooks and Weaver, plus an additional Pinboard. Prediction of discharge of patients hospitalized at the time of the study replicated previous results, including the finding that Pinboard scores were the most powerful single predictor. Job-finding was also predicted by the battery but with less efficiency. Psychomotor performance did not predict inpatient vs outpatient status at the time of testing. A composite score analysis suggests that the battery is a useful device for selection of candidates for psychiatric rehabilitation programs.

Antigens in immunity. XIV. Electron microscopic radioautographic studies of antigen capture in the lymph node medulla

Details of antigen trapping and processing in the rat lymph node have been investigated by the technique of high resolution radioautography. A series of 24 adult rats was injected with 20 microg of (125)I-labeled Salmonella adelaide flagella, given as either a primary or a secondary stimulus into one hind foot-pad. At intervals ranging from 3 min to 3 wk, rats were killed and the popliteal nodes were processed for electron microscopic radioautography using Kodak NTE emulsion. The present paper deals with events in the lymph node medulla, and an accompanying report describes the radically different behavior of antigen in the cortical follicles. In the medulla, lightly labeled granulocytes were transiently encountered, but by far the greatest bulk of antigen was in macrophages. Antigen entered these cells in two ways: by direct penetration of the plasma membrane; and by pinocytosis. In either case, the antigen rapidly became surrounded by tiny vesicles which may have represented Golgi-derived "protolysosomes." Vacuolar fusion ensued and a series of progressively larger and more complex antigen-containing "phagolysosomes" was formed. Substantial amounts of antigen could be detected in such bodies for at least 3 wk. The antigen injection, as expected, caused extensive plasma-cytopoiesis. No evidence of label in plasma cells was obtained. No special anatomic relationship between plasma cells and antigen depot sites was discovered. These results are briefly discussed in relation to current theories of immune induction.

Antigens in immunity. XV. Ultrastructural features of antigen capture in primary and secondary lymphoid follicles

This paper describes the trapping of antigen in lymphoid follicles of rat popliteal lymph nodes as revealed by electron microscopic radioautographs following injection of (125)I-labeled Salmonella adelaide flagella and other materials. The antigen was taken up vigorously, and to an approximately equal extent, by both primary and secondary follicles. The rate of uptake was faster in preimmunized than in virgin adult rats. The bulk of the antigen in follicles was extracellular, and persisted in this location for at least 3 wk. Label was most frequently found at or near the surface of fine cell processes. Many of these were branches of dendritic follicular reticular cells. Such processes interdigitated with equally fine processes of lymphocytes, creating an elaborate meshwork. In some cases, antigen was found between lymphocytes which appeared to be in close apposition. Occasionally, a few grains appeared over lymphocyte nuclei and study of serial sections suggested that this probably represented true entry of small amounts of antigen into lymphocytes. The characteristic "tingible body" macrophages (TBM) of germinal centers appeared to play only a secondary role in follicular antigen retention. They showed degrees of labeling over their phagocytic inclusions varying from negligible to moderately heavy. Moreover, follicles lacking or poor in TBM retained antigen just as effectively as those containing numerous TBM. The hypothesis is advanced that TBM may be derived from monocytes that migrate down from the circular sinus. Follicular localization of three other materials was also studied, though not in such detail. These were (125)I-HSA complexed to anti-HSA: (125)I-labeled autologous IgG; and (125)I-monomeric flagellin. All of these showed the basic features of intercellular, membrane-associated deposition noted with (125)I-flagella. The role of follicular antigen depots in immune induction is discussed. The tentative conclusion is reached that follicular antigen in a primary follicle encounters natural antibody on the surface of certain antigen-reactive lymphocytes. The resultant reaction causes blast cell transformation and eventually the genesis of a germinal center.

Use of droperidol and fentanyl for analgesia and sedation in primates

A combination of droperidol and fentanyl produces qualitatively similar pharmacologic effects in dogs and primates. Unlike the dog, however, primates did not appear to respond to auditory stimuli. As a result of the analgesic and sedative or tranquil state produced in primates, the animals were easily handled and tolerant of painful stimuli. The principal desirable features of the combination were high analgesic and sedative potency and a rapid onset of action following intramuscular administration. High doses produced respiratory depression. However, this effect was easily reversed by administering nalorphine hydrochloride.