bluuebunny/crossref_metadata_2025 huggingface dataset:
SYNERGISM OF THYMUS AND BONE MARROW IN THE PRODUCTION OF GRAFT-VERSUS-HOST SPLENOMEGALY IN X-IRRADIATED HOSTS
Authors: Hilgard Henry R.
Published: June 2004

Graft-versus-host splenomegaly may be elicited from 500 R X-irradiated F1 hybrid hosts if the hosts are injected with bone marrow cells and thymus cells from parental strain donors. Cells from thymus only or bone marrow only will not elicit graft-versus-host splenomegaly in these hosts. In this requirement for cells from both sources, the bone marrow cells play a nonimmunologic, proliferative role in the splenomegaly, and the thymus cells carry out the immunologic attack. Thus the mechanism of this synergism is quite different from that reported for the humoral immune response to sheep erythrocytes in which both thymus and marrow interact in the production of the specific immunologic response itself.
SUPPRESSION OF CELL-MEDIATED IMMUNITY TO INFECTION BY AN ANTIMITOTIC DRUG
Authors: North R. J.
Published: June 2004

The development of acquired cell-mediated immunity to infection with Listeria monocytogenes can be blocked by a 15 hr pulse of the antimitotic drug, vinblastine (Vb). The drug has no effect on the host-parasite relationship after 72 hr of infection when a high level of immunity is being expressed, i.e., when infective foci are populated by activated macrophages. Infective foci in mice treated early during infection with Vb do not acquire migrant macrophages, but they become acellular after 48 hr of infection. The results indicate that Vb destroys the dividing precursors of migrant macrophages. The possibility that Vb prevents the activation of these cells by destroying dividing lymphoid cells engaged in the specific immunological phase of the host response is also considered.
CELLULAR BASIS OF THE GENETIC CONTROL OF IMMUNE RESPONSES TO SYNTHETIC POLYPEPTIDES
Authors: Mozes Edna , Shearer G. M. , Sela Michael
Published: June 2004

SJL mice are high responders to the synthetic multichain polypeptide antigen (T,G)-Pro--L, whereas DBA/1 mice are low responders (10, 11). In order to determine whether the genetic control of immune response can be correlated with the number of antigen-sensitive precursor cells, spleen cell suspensions from normal and immunized SJL and DBA/1 donor mice were transplanted into lethally X-irradiated syngeneic recipients (incapable of immune response) along with (T, G)-Pro--L. Anti-(T, G)-Pro--L responses (donor-derived) were assayed in the sera of the hosts 12–16 days later. By transplanting graded and limiting numbers of spleen cells, inocula were found which contained one or a few antigen-sensitive precursors reactive with the immunogen. Using this method to estimate the relative numbers of such cells for the high responder SJL strain, one precursor was detected in ∼1.3 x 106 and ∼7.2 x 106 spleen cells from immunized and normal donors, respectively. In contrast, one precursor was detected in about 30 x 106 spleen cells from low responder DBA/1 mice, irrespective of whether the donors had been immunized.

These results indicate that the genetic control of immunity to the synthetic polypeptide antigen investigated is directly correlated to the relative number of precursor cells reactive with the immunogen in high and low responder strains.
A POPULATION OF LYMPHOCYTES BEARING A MEMBRANE RECEPTOR FOR ANTIGEN-ANTIBODY-COMPLEMENT COMPLEXES
Authors: Bianco Celso , Patrick Richard , Nussenzweig Victor
Published: June 2004

A population of lymphoid cells from several animal species, including man, was identified through a membrane receptor which binds sheep red blood cells treated with antibody and complement. When cells from different lymphoid organs were incubated with EAC at 37°C, only part of the lymphocytes (named CRL) bound EAC and formed rosettes, and this interaction was shown to be C3-dependent.

Mouse lymphoid cells could be specifically depleted of CRL by allowing them first to interact with EAC and then submitting the mixture to ultracentrifugation in a gradient of BSA. After ultracentrifugation, a population of cells containing 95% or more of non-CRL were recovered from the upper layers of the gradient.

In addition to their different abilities to bind EAC, CRL and non-CRL from mouse lymphoid organs could be distinguished by the following properties: (a) CRL adhered preferentially to nylon wool at 37°C in the presence of mouse serum. (b) After differential flotation in a gradient of BSA, a significantly higher proportion of CRL were recovered from the upper layers of the gradient. (c) The population of CRL contained most of the lymphocytes bearing immunoglobulin determinants on their membranes. (d) The distribution of CRL was quite different among lymphocytes obtained from various lymphoid organs, and they were never found in the thymus. (e) The membrane receptor for EAC was not detected in plaque-forming cells of mice which had been previously immunized with burro red cells.

CRL and non-CRL could not be distinguished by their life span, as they were found in similar proportions among long-lived and short-lived lymphocytes from mouse peripheral lymph nodes.

The function of this receptor on the membrane of certain lymphoid cells may be related to (a) the trapping and localization of antigen in lymphoid organs or (b) the localization of lymphoid cells in inflammatory sites.
DETERMINATION OF ANTIBODY CLASS IN A SYSTEM OF COOPERATING ANTIGENIC DETERMINANTS
Authors: Schirrmacher Volker , Rajewsky Klaus
Published: June 2004

19S and 7S memory is analyzed in a system of cooperating antigenic determinants. Cooperation occurs in the induction of both 19S and 7S secondary antibodies, and for both responses carrier specificity can be entirely accounted for by presensitization of the animal to carrier determinants.

The class distribution of secondary anti-hapten antibody depends on the dose of the hapten primary-carrier conjugate used for priming, and on the time interval between priming with the hapten primary-carrier conjugate and secondary injection. The conditions of priming with the secondary carrier influence the extent of the secondary response but not the class distribution of secondary antibody. The data confirm the cooperation hypothesis of antibody induction. Specifically, we interpret them to mean that in hapten-carrier cooperation, the hapten-specific memory cells are predetermined for the class of the emerging antibodies. Together with the hapten-specific memory cells, the carrier-specific helpers are responsible for the extent of the secondary response.
CELLULAR AND VASCULAR COMPONENTS OF THE ALLOGRAFT REACTION
Authors: Lambert Peter B. , Frank Howard A.
Published: June 2004

In order to gain added insight into the mechanisms of allograft destruction, skin grafts were returned to their original donors after remaining as allografts long enough to induce immunity in the intermediate host but not long enough to cause destruction of the graft.

Upon their return to unmodified donors, such grafts became revascularized and remained viable. An intense cellular infiltration was incited within the graft and its draining lymph node by the interaction between immunologically competent cells, some antigenically activated, that were transferred from the intermediate host with the graft, and those of the final host, the original donor. This immune interaction excited a nonspecific granulocytic and histiocytic response, which led to the destruction of the adjacent epithelium already re-accepted within its native habitat. This mechanism of epithelial destruction required vascular connection to permit the cellular infiltration, and was unlikely to have primarily involved circulating antibody.

When similar grafts were returned to donors that had been sensitized to the intermediate host, vascularization and reacceptance of the graft did not occur. No cellular infiltration took place in the graft and no lymph node response was evoked. The returned grafts were cast off as full-thickness sloughs. Here the mechanism of graft rejection was apparently an interaction between the preformed antibody of the specifically sensitized host and the allogeneic cells transferred from the intermediate host; this interaction prevented the vascularization of the graft, even though the endothelia involved were autologous.

In unmodified allografts, both the character and the variability of the histologic patterns can be accounted for by the superimposition, in differing rates and degrees, of humoral vascular effects upon cellular events already in progress.
AN ULTRASTRUCTURAL STUDY OF GLOMERULAR PERMEABILITY USING CATALASE AND PEROXIDASE AS TRACER PROTEINS
Authors: Venkatachalam M. A. , Karnovsky M. J. , Fahimi H. D. , Cotran R. S.
Published: June 2004

Mice were injected intravenously with beef liver catalase (mol wt 240,000) and very small doses of horseradish peroxidase (mol wt 40,000) and the site of localization of these enzymes in the kidney was studied by ultrastructural cytochemistry. 1 min after injection, catalase was present in glomerular capillary lumina and there was minimal permeation of the basement membrane. After 5–180 min, staining of the basement membrane increased progressively but was usually less than that in capillary lumina. At all time intervals the inner (sub-endothelial) layer of the basement membrane contained more reaction product than the lamina densa and the outer (subepithelial) layer. Catalase permeated the entire thickness of the basement membrane and extended up to the slit pore but not beyond the level of the slit diaphragm and was not seen in the urinary space or tubular lumina. Horseradish peroxidase permeated the whole thickness of the basement membrane within 2 min after injection; however, gradients of staining from the inner to outer layers of the basement membrane were frequently seen.

The findings with both enzymes indicate that (a) the basement membrane restricts the passage of proteins over a wide range of molecular size with increasing impediment for larger molecules and (b) the slit pore functions as an additional barrier for molecules that cross the basement membrane.
DEMONSTRATION OF HEAVY AND LIGHT CHAIN ANTIGENIC DETERMINANTS ON THE CELL-BOUND RECEPTOR FOR ANTIGEN
Authors: Walters Curla S. , Wigzell Hans
Published: June 2004

High-rate antibody-forming cells and immunological memory cells can be selectively retained if filtered through a column coated with relevant antigen. This trapping can be blocked if the cells are incubated with an anti-immunoglobulin serum prior to column passage. A similar blocking is not observed when cells are treated with an anti-lymphocyte serum, thereby excluding the possibility that any antibodies combining with surface structures could cause this effect. By the use of antisera specific for heavy or light chain antigens, it was possible to locate such antigens in the antigen-binding receptor areas of immune cells. Criss-cross studies using antisera specific for gamma 1 or gamma 2a heavy chains showed that the membrane receptor has the same heavy chain as will be present in the eventual product of that cell, the humoral antibody.
RESTRICTION OF HERPES SIMPLEX VIRUS BY MACROPHAGES
Authors: Stevens Jack G. , Cook Margery L.
Published: June 2004

Macrophages restrict herpes simplex virus replication and can prevent the development of herpetic disease in mice. In an attempt to define the nature of this restriction, an analysis of virus-specified macromolecular syntheses in infected macrophages was undertaken. The significant results were the following: All cells were killed, but the infection was considered to be abortive since the level of infectious virus in macrophage cultures dropped steadily to a level beyond detection by 25 hr after infection. This restriction appeared to be specific for macrophages; the virus replicated efficiently in other mouse cells. DNA with a density characteristic for herpes simplex virus DNA was extracted from infected cultures, and the proportion of macrophages synthesizing DNA increased from less than 1% to greater than 50% by 6 hr after infection. Studies employing polyacrylamide gel electrophoresis indicated that the major viral-specific proteins were induced in macrophage cultures. In addition, all cells showing cytopathic changes characteristic of herpes virus infection also contained viral antigens which could be detected by fluorescent antibody techniques and, by 15 hr after infection, most contained nascent capsids lacking central dense cores. It is suggested that an error in DNA metabolism may be the primary cause of restriction.
CELLULAR RECOGNITION IN VITRO BY MOUSE LYMPHOCYTES
Authors: Takiguchi T. , Adler W. H. , Smith R. T.
Published: June 2004

The effects of thymectomy and thymus graft restoration upon the in vitro primary responses to alloantigens and PHA have been studied. It has been found that neonatal thymectomy substantially eliminates both PHA reactivity and responsiveness to alloantigens assayed in vitro in host spleen cell populations. Analysis of albumin density gradient-separated subpopulations of the spleen and thymus in such animals was also performed. It was found that the total and proportional representation of the individual density subpopulations was identical in neonatally thymectomized, in normal, and in thymectomized and thymus graft-restored animals. Therefore, thymectomized mice appear to retain a nonfunctioning, small, dense, lymphocyte population. Reconstitution of thymic-dependent in vitro reactivity was nearly complete when syngeneic, but not allogeneic or semisyngeneic thymus was employed. Occasional partial restoration did occur when F1 thymus was employed, but never when allogeneic thymus was grafted. The grafted thymus contained PHA and alloantigen-reactive cells in a large, less dense B layer subpopulation, whereas the restored animals, as in the case of normals, showed these reactivities to be a property of a small, more dense cell population.
CELLULAR BASIS OF THE GENETIC CONTROL OF IMMUNE RESPONSES TO SYNTHETIC POLYPEPTIDES
Authors: Shearer G. M. , Mozes Edna , Sela Michael
Published: June 2004

DBA/1 mice are high responders to the (Phe, G) determinant of the synthetic polypeptide (Phe, G)-Pro--L, whereas SJL mice respond well to the Pro--L region of this macromolecule (6). In order to determine whether the phenomenon described above is related to the number of antigen-sensitive units detected for both specificities, and whether responses to these determinants can be transferred independently, graded and limiting inocula of spleen cells from SJL, DBA/1, and F1 donors were injected into X-irradiated, syngeneic, recipient mice with (Phe, G)-Pro--L.

By this approach, one antigen-sensitive unit specific for (Phe, G) was detected in 1.7 x 106 and 8.5 x 106 spleen cells from immunized and nonimmunized DBA/1 donors, respectively. In contrast, one (Phe, G) relevant precursor was detected in 20 x 106 SJL spleen cells, irrespective of whether the donors had been immunized. On the other hand, for the Pro--L specificity, one limiting splenic precursor was found in 1.3 x 106 and in 3.4 x 106 cells for immunized and nonimmunized SJL donors, respectively; whereas one response unit was estimated for this determinant in 9.4 x 106 and in 38 x 106 spleen cells from immunized and nonimmunized DBA/1 mice. The findings reported here indicate that the phenotypic expression of the genetic control(s) for immune responsiveness to different immunopotent regions of (Phe, G)-Pro--L is directly correlated with the number of immunocompetent response units detected in two inbred mouse strains.

In the spleens of immunized F1 donors, similar frequencies of one limiting precursor in 3.0 x 106 and in 2.8 x 106 cells were detected for (Phe, G) and Pro--L, respectively. The results of a chi-square test for independence of (Phe, G) and Pro--L responses in F1 animals is compatible with the hypothesis that the transferred spleen cells limiting the response to (Phe, G)-Pro--L are restricted to generate antibodies specific for only one of the two determinants of this macromolecule.
STUDIES ON ANTIBODY-PRODUCING CELLS
Authors: Gudat Fred G. , Harris T. N. , Harris Susanna , Hummeler Klaus
Published: June 2004

A study of the kinetics of antibody-producing cells has been carried out by the use of rosette formation for detection of individual antibody-producing cells, and labeling with tritiated thymidine, in cells obtained from mouse spleens at intervals after injection of SRBC. Following a primary injection of the antigen, the number of RFC per million cells was found to increase to a peak at 5 days, then, after a decrease, to a second peak at about the 10th day. The curve of tritium labeling of RFC was also biphasic, with peaks on the 3rd and 7th day. The second increase in rosette-forming cells could be shown to involve, especially between the 7th and 9th day, a second increase in lymphoid cell RFC and, among these, 7S antibody-producing cells. When the population examined was restricted to large lymphocytes, two peaks of RFC per million cells and two peaks of labeling were again found. In this case, however, the peaks of RFC and of labeling were reached on the same day in each instance, rather than with the 2 day difference found in the entire spleen cell suspension or the entire lymphoid cell population.

Electron microscopic examination of labeled rosette-forming cells showed these to be largely lymphocytes, but to include rather well differentiated plasmablasts as well. No macrophages were found among labeled RFC in the primary response. A substantial number of labeled lymphocytes were found in close contiguity with rosette-forming macrophages. The percentage of labeling in such lymphocytes was as high, on the respective days, as the percentage of labeled cells among the RFC of the entire suspension.
THE MOUSE INTESTINAL MICROFLORA WITH EMPHASIS ON THE STRICT ANAEROBES
Authors: Lee Adrian , Gordon James , Lee Chi-Jen , Dubos René
Published: June 2004

The various components of the intestinal microflora in the mouse become established according to a definite time sequence; the strict anaerobes are the last groups of bacteria to reach their maximum population levels, 14–16 days after birth.

The multiplication of these strict anaerobes in the mouse intestine seems to depend upon the prior multiplication of other bacterial species, and coincides with the ingestion of food other than maternal milk. These two conditioning factors may correspond to the establishment of a suitably reduced Eh potential and to the provision of certain metabolites.

Once established, the strict anaerobes constitute by far the largest percentage of the total intestinal microflora; most of them are associated in a viable form with the mucosa. In normal animals they persist at very high levels throughout the life span. However, their populations can be drastically reduced by dietary manipulation of the animal, by administration of vancomycin, or by certain disease processes of the intestine.

The strict anaerobic bacteria seem to play an important, and perhaps essential role in the maintenance of the anatomic structures and physiological functions of the intestine. They also seem to hold in check several species of intestinal bacteria, in particular the coliform bacilli.
RELATIONSHIPS BETWEEN RELATIVE BINDING AFFINITY AND ELECTROPHORETIC BEHAVIOR OF RABBIT ANTIBODIES TO STREPTOCOCCAL CARBOHYDRATES
Authors: Eichmann K. , Greenblatt J.
Published: June 2004

After repeated intravenous injections with Group C streptococcal vaccine, most rabbit antisera were shown to contain one or more IgG antibody components, as revealed by microzone electrophoresis. A procedure for the fractionation of multiple IgG antibody components from such streptococcal antisera is described. Separation is achieved on the basis of differences in relative binding affinities of the antibody components to immunoabsorbent columns. The evidence suggests that the electrophoretic mobility, and thus the net charge of an antibody, bears a reciprocal relationship to its binding affinity for the streptococcal Group C antigens. Furthermore, the relative binding affinity affords another means to assess the functional homogeneity of streptococcal antibodies. A possible relationship between light chain variable-region subclasses and binding affinities of streptococcal antibodies is discussed.
QUANTITATIVE STUDIES ON THE MIXED LYMPHOCYTE INTERACTION IN RATS
Authors: Wilson Darcy B. , Nowell Peter C.
Published: June 2004

These studies were designed to determine what influence prior immunization with homologous H isoantigens might have on the subsequent proliferative activity of lymphocytes from these animals in the mixed lymphocyte interaction. The results demonstrate the following: (a) Subcutaneous immunization with splenic cells from donors differing at the major H locus accelerates the tempo of the proliferative response to F1 cells bearing these same antigens in the MLI, whereas antigen given systemically reduces the proliferative response. (b) The altered proliferative behavior is specific for the immunizing antigens. (c) The period after immunization during which the MLI displays an altered tempo is a short one, lasting not longer than 3 wk. (d) Whether they are derived from previously immunized or from normal donors, the proportion of lymphocytes responsive in the MLI is the same, even though the response profiles are different.

These results suggest that in comparison to immune responses to other types of antigens, immunologic reactivity to the major H isoantigens already involves a large number of antigen-reactive cells in normal animals and that the proportion of these cells is not increased as a result of immunization. Rather, lymphocytes from immunized animals respond more rapidly to the presence of these antigens.
PARTICIPATION OF THREE CELL TYPES IN THE ANTI-SHEEP RED BLOOD CELL RESPONSE IN VITRO
Authors: Tan Teresita , Gordon Julius
Published: June 2004

Spleen cells of unprimed CBA mice were shown to produce anti-sheep red blood cell antibodies comparable in amount in vivo and in vitro. Under identical culture conditions spleen cells of C57BL mice did not respond. CBA spleen cells, passed through columns of cotton wool (CBAf), were equally inactive in vitro. However combined cultures containing both CBAf and C57BL cells yielded as many or more plaque-forming cells than the same number of unfractionated CBA spleen cells. Analysis of the contribution of each cell population to the synthesis of antibody in the combined cultures has disclosed the participation of three cell types. A thymus-dependent, radiosensitive cell was derived from the CBAf population, while the C57BL was the source of the precursor of the antibody-forming cell and of a radioresistant cell. The latter two were partially separated in a Staput apparatus.
MECHANISMS UNDERLYING BINDING OF IMMUNE COMPLEXES TO MACROPHAGES
Authors: Phillips-Quagliata Julia M. , Levine Bernard B. , Quagliata Franco , Uhr Jonathan W.
Published: June 2004

The mechanism of binding of immune complexes to macrophages was investigated using purified antibody and haptens of different valences. Antibody alone bound to macrophages; enhancement of binding occurred when polyvalent and divalent haptens were present at equivalence but did not occur in great antigen excess. Monovalent hapten did not increase the binding of antibody at any concentration ratio tried, though it inhibited the enhancement due to oligovalent hapten. Ultracentrifuged normal rabbit globulin also inhibited the binding of complexes indicating the presence of exposed binding sites on the uncomplexed molecules. Complexes bound more strongly than antibody alone as determined from elution studies. These results support the hypothesis that the enhancement of antibody binding to macrophages in the presence of antigen is due to increased energy of binding resulting from summation of individual binding sites already exposed on the antibody molecules.

It was also possible, by saturating the macrophages with gamma globulin, to estimate the number of binding sites per cell; this was calculated to be approximately 2 million per alveolar macrophage.
AN EOSINOPHIL LEUKOCYTE CHEMOTACTIC FACTOR OF ANAPHYLAXIS
Authors: Kay A. B. , Stechschulte Daniel J. , Austen K. Frank
Published: June 2004

The capacity of actively or passively sensitized guinea pig lung to react with antigen to release a factor specifically chemotactic for eosinophil leukocytes (ECF-A) has been demonstrated. The release of ECF-A was also accompanied by the elaboration of both histamine and SRS-A and the appearance of all these mediators exhibited a similar response in terms of the time course of passve sensitization, the effect of antigen dose, the time course of release, divalent cation dependence and enhancement by the presence of succinate or maleate. Decomplementation by the administration of purified cobra venom factor had no effect on the antigen-induced release of ECF-A from actively or passively sensitized lung fragments.

When fragments of guinea pig lung were passively sensitized with fractions of guinea pig 7S IgG, only the IgG1-containing fractions prepared tissue for the antigen-induced release of ECF-A. Histamine, SRS-A, bradykinin, serotonin, and the prostaglandins PGE1, PGE2, and PGF2α were not eosinophilotactic per se; neither was ECF-A detected following the incubation of these agents with sensitized lung in the absence of antigen.

Both eosinophilotactic activity and SRS-A survived extraction in 80% ethanol and evaporation to dryness. SRS-A, however, withstood boiling in alkaline solution for 20 min, whereas ECF-A activity was abolished by this procedure. SRS-A and ECF-A could also be separated by gel filtration. ECF-A activity was completely recovered following its passage through a column of Sephadex G-25 and had an estimated molecular weight of between 500 and 1000. On the basis of size and a formation mechanism independent of the complement system, ECF-A is distinguishable from a previously described complement-dependent eosinophilotactic factor (ECF-C). Thus, ECF-A represents a hitherto undescribed agent which selectively attracts eosinophil leukocytes.
IN VITRO ORGANIZATION OF DISSOCIATED RAT CARDIAC CELLS INTO BEATING THREE-DIMENSIONAL STRUCTURES
Authors: Halbert S. P. , Bruderer R. , Lin T. M.
Published: June 2004

When isolated beating ventricular heart cells from newborn rats were grown in tissue culture on untreated polystyrene surfaces, they showed a striking tendency to grow focally in three dimensions from the single layer cell sheets which were formed early in growth. During this process, they frequently formed miniature spherical heart-like masses, which continued to beat and grow in size. These often were somewhat lobulated in appearance, and grew up to 2 mm in diameter. Histological sections of such structures sometimes revealed evidence of appreciable orientation of the cells to each other, in fiber-like units. Electron microscope sections of such mini-hearts showed structures resembling intercalated discs between myocardial cells. The precise factors which induced the cardiac cells to apparently organize into these heart-like structures are not presently known.
MACROPHAGE PLASMA MEMBRANES
Authors: Nachman Ralph L. , Ferris Barbara , Hirsch James G.
Published: June 2004

Plasma membranes have been isolated from pure populations of rabbit alveolar macrophages which were swollen in water, fixed briefly with glutaraldehyde, disrupted by Dounce homogenization, and separated by sucrose gradient centrifugation. The recovered membranes exhibited good structural preservation and enzymatic activity; both morphologic and biochemical evidence indicated a high degree of purity (>90%) of the membrane preparation.

Interiorized plasma membranes were also prepared without exposure to glutaraldehyde from phagocytic vacuoles recovered from alveolar macrophages which had ingested large numbers of polystyrene spheres. These membranes were contaminated with lysosomal constituents, but they were nevertheless of value for comparison to the "pure" membranes isolated by the glutaraldehyde procedure.

Acrylamide gel electrophoresis of the solubilized plasma membranes and phagolysosomal membranes revealed similar protein patterns, with seven to nine individual components ranging in molecular weight from 70,000 to 140,000. The two most rapidly migrating components gave positive reactions for lipid as well as protein. A band containing carbohydrate was detected near the origin of the plasma membrane gels.

Antisera were made by injecting guinea pigs with the purified rabbit alveolar macrophage plasma membranes. Gel diffusion and immunoelectrophoretic study of these antisera established the presence of rabbit immunoglobulin G and of one or two other antigenic constituents in the membrane preparation.
REJECTION OF TUMOR ALLOGRAFTS BY MOUSE SPLEEN CELLS SENSITIZED IN VITRO
Authors: Cohen Irun R. , Globerson Amiela , Feldman Michael
Published: June 2004

This paper reports a model system of cellular immunity in which allosensitization of mouse spleen cells is induced in vitro. Allosensitization was achieved by culturing spleen cells upon monolayers of allogeneic fibroblasts. The ability of the spleen cells to inhibit the growth of tumor allografts in vivo served as a functional assay of sensitization. We found that unsensitized spleen cells or spleen cells sensitized against unrelated fibroblast antigens had no inhibitory effect on the growth of allogeneic fibrosarcoma cells when they were injected together into irradiated recipients. In contrast, spleen cells which were specifically allosensitized in vitro were found to be highly effective in inhibiting the growth of an equal number of allogeneic tumor cells. Several times more spleen cells from mice sensitized in vivo were required to produce a similar immune effect. This confirms the findings of previous studies which indicate that sensitization in cell culture can promote the selection of specifically sensitized lymphocytes.

Preincubating sensitizing fibroblasts with allo-antisera blocked the allosensitization of spleen cells. This suggests that antibodies binding to fibroblasts may inhibit the induction of sensitization by competing with lymphocytes for antigenic sites.

Mouse spleen cells which were able to recognize and reject tumor allografts in vivo were unable to cause lysis of target fibroblasts in vitro. Such fibroblasts, however, were susceptible to lysis by rat lymphoid cells sensitized by a similar in vitro method. These findings indicate that the conditions required for lymphocyte-mediated lysis of target cells may not be directly related to the processes of antigen recognition and allograft rejection in vivo.
THE PHLOGISTIC ROLE OF C3 LEUKOTACTIC FRAGMENTS IN MYOCARDIAL INFARCTS OF RATS
Authors: Hill Jeffrey H. , Ward Peter A.
Published: June 2004

An improved method is described for extraction from rat myocardium of an enzyme that cleaves the third component of complement (C3) into leukotactic fragments. Direct cleavage of C3 has been shown by the use of a radiolabeled preparation of human C3. The enzyme elutes slightly beyond (retarded to) an albumin marker in gel filtration.

After surgical ligation of a coronary artery, leukotactic activity can be extracted from infarcted rat myocardium. Described in terms of its time of appearance in infarcted tissue, the leukotactic activity has been identified as cleavage products of rat C3. The C3 fragments are of low molecular weight and heterogenous in size.

Rats, if treated with the C3 inactivator (isolated from cobra venom) so as to ablate serum C3, fail to develop leukotactic activity in the infarcted myocardium. In turn, few if any of the usual intense accumulations of neutrophils in response to infected myocardium are seen during the first 48 hr after coronary artery ligation.

These studies suggest a nonimmunologic role for C3 in the mediation of the acute inflammatory response in nonspecific tissue injury.
SKIN HOMOGRAFTS: TOLEROGENIC VERSUS IMMUNOGENIC INFLUENCES IN MICE
Authors: Wachtel Stephen S. , Silvers Willys K.
Published: June 2004

In strain combinations involving multiple non-H-2 disparities, neonatal skin grafts may survive significantly longer than adult grafts of similar genotype on normal adult hosts, and repeatedly outlive grafts of adult origin on immunosuppressed recipients. Moreover, newborn grafts of long-standing may render their hosts unresponsive to adult skin grafts from the same donor strain. With some H-2-compatible strain combinations in which homozygous neonatal grafts are rejected, F1 hybrid (heterozygous) grafts of similar age not only may survive indefinitely, but also may induce tolerance of subsequent adult parental strain homografts. These tolerogenic and gene dosage effects, although much weaker, can likewise be revealed with H-2-incompatible neonatal skin grafts.
THE FACTOR OF IMMUNIZATION IN THE RAT
Authors: Ford William L. , Simonsen Morten
Published: June 2004

Using a popliteal lymph node weight assay the graft-versus-host activity of lymphocytes from donors immunized with allogeneic tissue has been assayed by comparison with that of lymphocytes from nonimmune donors. When the donors were immunized against weak histocompatibility antigens (non-AgB) the specific GVH activity of its lymphocytes was increased. This increase was greater if spleen cells rather than thoracic duct lymphocytes were the source of the donor cells used for assay. The increase in GVH activity was also greater if the standard immunization procedure of two successive skin allografts was followed by three boosting injections of allogeneic lymphoid cells.

When donors were immunized against strong histocompatibility antigens the specific GVH activity of the donors' lymphocytes was slightly increased, was unchanged, or was actually decreased depending on the experimental situation. In donors rendered incapable of a humoral alloantibody response by whole body X-irradiation, immunization across a strong barrier was followed by little or no increase in the specific GVH activity of TDL. In the rat, as in other species, the increase in GVH activity after immunization is inversely proportional to the strength of the antigenic barrier involved.
EVIDENCE FOR RECENT DUPLICATIONS AMONG CERTAIN GAMMA GLOBULIN HEAVY CHAIN GENES
Authors: Natvig J. B. , Michaelsen T. E. , Kunkel H. G.
Published: June 2004

A survey of a large number of human sera with the heavy chain genetic markers of the γ-globulin system has revealed an unusual gene complex which is inherited as a unit through two different families. The gene complex involves two pairs of γG1 genetic markers which ordinarily behave as homoalleles, Gmz and Gmf for the Fd part of γG1 molecules, and Gma and non-a for the Fc part. Isolation of the γG1 fraction from the unusual sera demonstrated the presence of the important non-a antigen in the γG1 fraction. Through the use of immunoadsorbents it was shown that these antigens were not part of a single molecule but that separate molecules were involved. The accumulated evidence indicated that the appearance of such homoalleles on the same chromosome probably resulted from a recent gene duplication, giving rise to two γG1 cistrons on one chromosome.
THYMUS-MARROW IMMUNOCOMPETENCE
Authors: Cohen J. John , Claman Henry N.
Published: June 2004

Corticosteroids suppress the humoral antibody response of mice to sheep erythrocytes. This response depends on interactions between thymus-derived helper cells and bone marrow-derived antibody-forming cell precursors (AFC precursors). Previous experiments had shown that spleen cells (a mixture of thymus-derived and marrow-derived cells) were sensitive to corticosteroids while AFC precursors in the bone marrow were resistant. The present experiments showed that the thymus of a mouse given 2.5 mg of hydrocortisone acetate, although containing only about 5% of the number of cells of a normal thymus, was as effective as a normal thymus in cooperating with bone marrow when transferred to irradiated syngeneic mice and stimulated with SRBC. The proliferative response of thymus helper cells to SRBC was also resistant to hydrocortisone.

In this context, the majority of thymic cells are in the cortex, are rapidly dividing, are sensitive to corticosteroids and are not iminunocompetent. A small number of thymic cells, probably located in the medulla, are resistant to corticosteroids, but are immunocompetent since they can serve as helper cells.

The hydrocortisone-sensitive phase of the splenic response to SRBC was found to be the bone marrow-derived AFC precursor since spleens from hydrocortisone-treated donors had immunocompetence restored by normal bone marrow but not by normal thymus cells.
FURTHER STUDIES ON THE ULTRASTRUCTURE OF DIMERIC IGA OF HUMAN ORIGIN
Authors: Bloth Björn , Svehag Sven-Eric
Published: June 2004

Human colostral IgA and myeloma dimer IgA were purified and examined in the electron microscope using a modified technique of negative staining. Both types of preparation contained double Y-shaped structures of the dimensions: Fab region, 35 x 70 A, and the sum of the two Fc regions, 40 x 140–155 A. Colostral IgA as well as myeloma dimer IgA molecules showed a tendency of bending at the point where the Fc regions joined. Secretory component bound to dimer IgA produced no visible alteration of the molecule. Mild reduction and alkylation of colostral IgA yielded single Y-shaped 7S monomers with the dimensions, Fab, 35 x 70 A, and Fc, 40 x 65–70 A.
FURTHER STUDIES OF ANTIGENIC COMPETITION
Authors: Kerbel R. S. , Eidinger David
Published: June 2004

A striking correlation between the capacity of an antigen to nonspecifically suppress humoral immune responses of subsequently administered antigens which are non-cross-reacting, i.e. to manifest antigenic competition and produce enlargement of spleen size through cell proliferation, was found. Increase in spleen size was always accompanied by a drop in the normal proportion of thymus-derived cells to non-thymus-derived cells.

Various means of altering the immune response to the initial antigen, and hence, the capacity of that antigen to suppress in a model of antigenic competition were performed and correlated with changes in spleen size and in the proportion of θ-positive cells in the spleen. In all instances, when the experimental condition reduced or abolished antigenic competition, the increase in spleen size and reduction in the proportion of θ-positive cells in the spleen was reduced or abolished. Furthermore, under conditions in which the suppressive capacity of the initial antigen was unaltered, the increase in spleen size and reduction in θ-proportion occurred normally. Finally, the better the suppression in a model of antigenic competition, the greater the increase in spleen size and reduction in the proportion of θ-positive cells.

On the basis of these observations, it appears that there is a relationship between spleen enlargement through clonally restricted cell proliferation and the expression of antigenic competition; one cannot have the latter without the former. It is postulated that the immunological lesion associated with antigenic competition resides at the level of interference with cell interaction between thymus-derived antigen-reactive cells and marrow-derived antibody-forming cells. This occurs as a result of a relative "diluting out" of cells of both populations carrying antigenic specificity differing from the one(s) which induced the dilution effect in the first place. The net effect of this is to decrease the chance of a "hit" or interaction between a marrow-derived and thymus-derived cell of the same specificities.

This mechanism, which is compatible with theories of clonal selection, and which in fact is dependent upon them, supports the view that the term "antigenic competition" is a misnomer; there is no competition by the antigens for anything. The term "antigen-induced suppression" is suggested as a more suitable alternative.
PURIFICATION AND PHYSICAL PROPERTIES OF GROUP C STREPTOCOCCAL PHAGE-ASSOCIATED LYSIN
Authors: Fischetti Vincent A. , Gotschlich Emil C. , Bernheimer Alan W.
Published: June 2004

A purification procedure for the Group C phage-associated lysin is described utilizing tetrathionate to protect the enzyme's -SH group(s) from thiol-inactivating agents. A 652-fold purification has been accomplished yielding a solution in which the enzyme activity corresponds to essentially a single band on polyacrylamide gel which accounts for 70% of the total protein in the preparation. A molecular weight of 101,000 and frictional ratio of 1.526 was determined for the lysin utilizing experimentally determined values for its Stokes radius and sedimentation coefficient.
STUDIES ON THE LIFE HISTORY OF LYMPHOCYTES
Authors: Nowell Peter C. , Wilson Darcy B.
Published: June 2004

The life history, within the rat, of lymphocytes responsive to histocompatibility isoantigens in the mixed lymphocyte interaction was examined by the use of in vivo labeling with tritiated thymidine and radioautography. Lymphocytes in the peripheral blood and H-ARC (mitotic figures in the MLI) were compared with respect to the frequency of labeled cells and the median grain count. The following conclusions were drawn from this study: (a) Although some can be considered long-lived, the majority of H-ARC are the products of recent divisions in the body. (b) Adult thymectomy does not eliminate the production of long-lived lymphocytes, some of which are H-ARC. Hence, in addition to direct origin in the thymus, H-ARC, as well as other lymphocytes of the long-lived lymphocyte population, may derive from already existing thymus-derived cells in the circulation and thymus-dependent areas of the secondary lymphoid tissues. (c) Sublethal X-irradiation (600 R) in combination with adult thymectomy does not eliminate the capacity to produce some long-lived lymphocytes, however, few if any are H-ARC. (d) H-ARC and other long-lived lymphocytes appear to go through a series of rapid multiple divisions before they enter the circulation. Thereafter, long-lived lymphocytes appear to undergo intermittent single divisions which decrease both the frequency and median grain count of labeled cells gradually with time. On the other hand, labeled H-ARC maintain a more stable grain count despite a rapid decrease in frequency with time. This is taken to indicate that H-ARC are less likely to undergo occasional single divisions during their life-span, but may undergo periodic rapid sequential divisions.

A speculative model is developed from these data on the life history of H-ARC which may be of predictive value in future studies and which can be tested against known facts.
ANTIGEN-SPECIFIC CELLS IN MOUSE BONE MARROW
Authors: Miller Harold C. , Cudkowicz Gustavo
Published: June 2004

Quantitative and qualitative changes of mouse bone marrow cells were studied by limiting dilution assays 2–3.5 months after immunization of donors with sheep erythrocytes or unrelated antigens (Salmonella typhimurium, horse and chicken erythrocytes). Irradiated (C3H x C57BL/10)F1 mice were reconstituted with an excess of nonprimed thymocytes and small graded numbers of primed bone marrow cells. Direct and indirect plaque-forming cells (PFC) were induced by secondary stimulation with SRBC and enumerated on the 9th day after cell transplantation.

Marrow precursors of PFC (P-PFC) cooperated with thymocytes in the production of direct and indirect PFC after SRBC priming. The limiting dilution plots, which were not compatible with predictions of the Poisson model before immunization, changed and conformed to this model afterwards, as if the population of P-PFC had become functionally more homogeneous. The concentration of marrow P-PFC increased up to the 3rd month after priming, and decreased during the 4th, varying over two logarithms of nucleated marrow cells. The fluctuation was simultaneous and of the same order of magnitude for precursors of direct and indirect PFC, which were class restricted. A third effect of immunization was detected at 3.5 months: individual precursor units generated 3–4 times more direct and indirect PFC than at earlier intervals. Qualitative and quantitative changes of marrow P-PFC participating in anti-sheep responses were specific, since antigens unrelated to SRBC failed to induce them. The data suggested that marrow-derived cells were the major carriers of immunologic memory, but that they functioned in cooperation with thymus-derived inducer cells during secondary anti-sheep responses.
REGULATION OF THE IMMUNE RESPONSE: SUPPRESSIVE AND ENHANCING EFFECTS OF PASSIVELY ADMINISTERED ANTIBODY
Authors: Pincus Carolyn S. , Lamm Michael E. , Nussenzweig Victor
Published: June 2004

The ability of passively administered antibody to suppress the immune response against homologous antigenic determinants while concomitantly enhancing the response against other unrelated determinants of the same antigen molecule has been established in two distinct antigen-antibody systems: (a) guinea pig γ2-immunoglobulin + passive anti-F(ab')2 antibody, where suppression of anti-F(ab')2 antibody synthesis is accompanied by enhancement of the anti-Fc response; and (b) human secretory IgA + passive anti-serum IgA antibody, where suppression of antibody production against the α and L chains accompanies augmentation of the response to the secretory component.

The mechanisms of the suppressive and enhancing effects are probably unrelated for the following reasons: (a) Enhancement of the response to certain determinants may be obtained without discernible suppression of the response to the homologous determinants; and (b) the F(ab')2 fragments of passive antibody can mediate immune suppression but were not observed to enhance the response against the unrelated determinants of the same antigen molecule. Also, the timing for achieving maximum suppression or enhancement of antibody formation is not the same; enhancement was obtained only at a later time.

Both the enhancement and suppressive effects were obtained with the purified γG fraction of antisera. This finding rules out an exclusive role of γM antibody in the enhancement phenomenon.
ANTIGEN RECOGNITION AND ANTIBODY SPECIFICITY
Authors: Levin Howard A. , Levine Herbert , Schlossman Stuart F.
Published: June 2004

The exact specifiicity of anti-DNP antibody produced by Hartley guinea pigs immunized with a series of defined α,DNP and ϵ,DNP-oligolysines was studied by fluorescence quenching. All responder animals made anti-DNP antibody which recognized the precise chain length, ± 1 lysyl residue, of the DNP-oligolysines used to induce the immune response as measured by an increase in binding energy (–ΔF°) for that antigen. The ability of the immune system to detect the smallest possible change in oligolysine chain length suggests that the anti-hapten antibody-forming cell possesses a highly specific recognition system for carrier conformation. When DNP-oligolysines are incorporated in an adjuvant containing M. tuberculosis H37Rv, both responder and nonresponder produce anti-DNP antibody, but only the responder develops delayed skin sensitivity. In addition to their failure to develop delayed hypersensitivity, nonresponders produced anti-DNP oligolysine antibody which did not show the increase in –ΔF° for the immunizing antigen characteristic of responder antibody. These observations support a local environment hypothesis for antigen recognition at the level of the anti-hapten antibody-forming cell and suggest that the polylysine gene exerts its control at the same cell.