Antigenic markers on mouse lymphoid cells: origin of cells mediating immunologic memory

Specific antisera were used for the purification of thymus dependent and thymus independent or bursa equivalent lymphoid cells in the mouse. Spleen cells from mice immune to sheep erythrocytes, a thymus dependent antigen, or to E. coli 055:B5 lipopolysaccharide, a thymus independent antigen, were treated with anti-θ (C3H) serum or anti-MBLA serum and complement prior to their adoptive transfer into lethally irradiated syngeneic recipients. Syngeneic thymocytes, bone marrow cells, or spleen cells from nonimmune donors were appropriately added to antiserum treated cells prior to transfer. The secondary response to these antigens was assayed in recipient spleens six days after cell transfer. The kinetics of the primary response to SRBC was investigated as to its effect on origin of specific hyper-reactive T or B lymphoid cells.The adoptive response to CPS originated in the B lymphoid cell population. Immunologic memory to CPS was demonstrated in recipients of immune cells, compared to recipients of normal cells, by a five fold increase in antibody forming cells.The IgM and IgG adoptive immune response to high doses of SRBC depended upon an increased number of specifically hyper-reactive T-lymphoid cells to facilitate cooperation between T and B lymphocytes. High doses of SRBC initially stimulated T cell memory but at 42 days after priming an increased number of specifically hyper-reactive B lymphoid cells were present.     

Secondary delayed-type hypersensitivity to sheep red blood cells in mice: a long-lived memory phenomenon

Immunization of mice with sheep red blood cells (SRBC) can induce the capacity to react with a secondary delayed-type hypersensitivity (DTH) immune response upon a booster injection of the antigen. In this paper the kinetics of secondary DTH after intravenous (iv) immunization with various doses of SRBC was studied by means of the foot swelling test. Dose-response studies showed that maximal secondary DTH responsiveness was obtained by iv administration of a priming dose of 3 × 10⁴ SRBC and a booster dose of 3 × 10⁵ SRBC 2 months later. Secondary DTH in such treated mice was characterized by an earlier appearance of the state of DTH, an earlier peak reactivity, and an increased intensity of the DTH response as compared to the primary DTH response. Up to 1 year after priming, a secondary DTH could be elicited, indicating the long-lived character of this memory phenomenon. With increasing intervals between the priming and booster injection, a gradual shift to a later time, of the peak secondary DTH reactivity was found. The capacity of primed mice to react with an increased intensity upon a booster injection could be adoptively transferred into lethally irradiated recipients by means of spleen cells obtained from primed mice. This phenomenon appeared to be highly dependent on Thy 1.2⁺ cells and on the booster dose of SRBC. The DTH reaction, evoked in such recipients, showed a prolonged time course.     

Antibody formation in mouse bone marrow. IX. Peripheral lymphoid organs are involved in the initiation of bone marrow antibody formation.

Mouse bone marrow is barely capable of plaque-forming cell (PFC) activity during the primary response to sheep red blood cells (SRBC). However, during secondary-type responses, it becomes the major organ, containing IgM, IgG, and IgA PFC. In the present paper, the influence of splenectomy (Sx) upon the secondary bone marrow PFC response to SRBC was investigated. When previously primed mice were splenectomized just before the second intravenous (iv) injection of SRBC, the effect of Sx upon the height of the bone marrow PFC response was dependent on the booster dose. Sx just before a booster of 10⁶ SRBC iv almost completely prevented bone marrow PFC activity, whereas an iv booster dose of 4 × 10⁸ SRBC evoked a normal IgM, IgG, and IgA PFC response in Sx mice. Apparently low doses of iv administered antigen require the spleen in order to evoke antibody formation in the bone marrow. Experiments with parabiotic mice, consisting of Sx and sham-Sx mice, showed that this facilitating influence of the spleen upon bone marrow antibody formation occurs via the blood stream. In a subsequent study, it was investigated whether the spleen is required throughout the bone marrow PFC response or only during the few days of the initiation phase. Therefore, mice were splenectomized at different intervals after a booster injection of 10⁶ SRBC iv. It appeared that Sx 2 days after the booster injection could still prevent the normal bone marrow PFC activity, whereas Sx at Day 4 could no longer do so. Apparently, after an iv booster injection, the spleen is only required for initiation of the bone marrow PFC response and not for the maintenance of this PFC activity thereafter.     

Alterations in the Immunogenic Properties of Sheep Erythrocytes by Sonic Disruption

A solubilized sheep red blood cell (SRBC) antigen (supernatant fraction obtained by centrifuging 10^7-2 × 10⁸ sonicated SRBC at 6 × 10⁴ g for 30 min [Sup-SRBC]), whose ability to inhibit anti-SRBC plaque formation was 70% of that of the original sonicated SRBC, was unable to elicit a detectable antibody response in either unprimed or SRBC-primed mice. However, Sup-SRBC as well as intact SRBC antigens generated memory for the secondary response, which was transferable to irradiated syngeneic recipients by injection of immune spleen cells. The memory generated by Sup-SRBC involved helper memory for anti-trinitrophenyl group (TNP) response to challenge with TNP-conjugated SRBC. Increase in the helper T cell memory in the spleens of Sup-SRBC-primed mice was also demonstrated by an in vitro culture experiment and by an adoptive cell transfer experiment. In contrast, no detectable B cell memory was generated by Sup-SRBC. Repeated stimulation with Sup-SRBC never induced significant antibody response but reduced the level of memory. A single injection of a low dose (10⁶) of SRBC also failed to induce a definite primary antibody response generating memory for the secondary response. However, repeated stimulation with this dose of SRBC induced a high antibody response and generated good memory. From these results it is suggested that the intact structure of SRBC is required for the activation of B cells, but is not necessary for the stimulation of T cells.     

Passive administration of antibodies during the primary immunization. The influence on the secondary response

Groups of mice were injected with different quantities of sheep red blood cells (SRBC: 10⁸, 10⁹ and 10¹⁰) and simultaneously with different quantities of antibodies against SRBC. The response was tested 15 and 30 days after the primary dose and 4 days after the secondary response. The action of antiserum regulates the quantity of antigen available for the immunization process. With a large dose of antiserum it is possible to inhibit the primary, as well as the secondary response. A smaller dose of antiserum suppresses primary antibody formation but the process of preparing the secondary response is not inhibited. An inhibitory dose of antiserum injected 24 and 48 hours after antigen significantly depresses the primary response but is followed by a pronounced secondary response. When the antigen is bound 24 and 48 hours after the primary stimulus, the secondary response is only of the 19S type. If the antigen is present at least 72 hours after the primary dose of antigen cells forming 7S antibodies appear also in the secondary response. Experimental data support the hypothesis that there is a common precursor cell for the 19S and 7S Ab-forming cell; during limited proliferation the cellular basis for the 19S secondary response and with intensive proliferation (only after 6 or 7 generations) the precursors for 7S antibody forming cells, appear. Dedicated to Academician Ivan Málek on the occasion of his 60th birthday     

Ascaris suum: Immunosuppression in mice during acute infection

Mice inoculated by stomach intubation with 10,000 embryonated Ascaris suum eggs, 4, 11, or 21 days before an intraperitoneal (ip) immunization with 2 × 10⁸ sheep erythrocytes (SRBC) had reduced numbers of direct (IgM) splenic hemolytic plaques measured at 4 days after immunization and only a marginal reduction in indirect plaques (IgG) measured at 9 days after immunization. Lower dosages of Ascaris eggs or simultaneous inoculation of Ascaris eggs and SRBC did not suppress antibody responses to SRBC. No reduction in a secondary antibody response to SRBC injected 4 days after Ascaris inoculation was observed. IgM and IgG hemagglutinin titers, as distinguished by 2-mercaptoethanol sensitivity, were suppressed in mice injected ip with 10⁸ SRBC 10 days following inoculation of 10,000 Ascaris eggs, but titers in both Ig classes were similar in infected and control mice injected with 2 × 10⁹ SRBC. At Day 20, antibody titers following ip injection of 1.0 or 100 μg of ovalbumin in alum were reduced in mice infected with 10,000 Ascaris eggs 4 days before antigen injection.Contact hypersensitivity to oxazalone was not altered in mice sensitized at 5 or 14 days after inoculation of 10,000 Ascaris eggs. The delayed hypersensitivity response, measured by footpad swelling, to an optimum intravenous sensitizing dosage of SRBC was inhibited in mice sensitized 10 days after Ascaris infection, but not inhibited in mice sensitized at 21 or 32 days after infection. In contrast, the delayed hypersensitivity response to subcutaneous sensitization with SRBC 10 days after Ascaris infection was not altered.     

Modulation of mouse anti-SRBC antibody response by placental extracts

Mouse placental extracts (PE) and corresponding Sephadex G-200 fractions were administered to isogeneic CBA mice along with an optimal immunizing dose of SRBC. Spleen cells were harvested 8 days later and transferred to CBA recipients, subsequently immunized with SRBC. The immunoregulatory activity of spleen cells from PE-treated donors was compared to cells from liver extract (LE)-treated controls or from mice immunized with SRBC only, using Cunningham's PFC direct and indirect tests. Within the dose range used, selective modulatory activities were obtained with cells from PE, but not from LE, treated mice, the latter being comparable to cell transfer effects from donors immunized with SRBC only. Spleen cells from animals injected with low doses of PE (0.25 to 4 mg per mouse) added to immunizing SRBC had a suppressive effect on the primary IgM response of recipients immunized against SRBC. In contrast, when SRBC were given to donor animals with higher doses of PE (8 to 13 mg), transferred spleen cells potentiated the IgM response of the recipients. These opposite suppressive and potentiating activities were found in distinct Sephadex G-200 fractions of 40 and 60 kDa, respectively. When the effect of PE treatment was tested within the same animal, the indirect secondary PFC response following a challenge with SRBC was significantly modified. We observed an overall suppression of the different isotypes after treatment with lower doses of PE or with its 40-kDa fraction. PE doses of 0.5 to 2 mg resulted in a stronger inhibition of IgM than IgG₁ production. This phenomenon was also obtained with the 40 KDa fraction. IgG₂ responses were significantly reduced by all doses of this fraction. In contrast, all doses of the 60-kDa fraction gave a strong stimulation of IgG₂ and IgM responses and a constant suppression of the IgG₁ response. This shows a clear dissociation between IgG₁ and C'-fixing (IgM, IgG₂) antibody classes as far as the influence of placental substances is concerned in their regulation. These data emphasize the relevance of isogeneic placental products as a useful physiological material capable of modulating xenogeneic immune responses (as well as allogeneic systems).     

Dose-Dependent Induction of Murine Th1/Th2 Responses to Sheep Red Blood Cells Occurs in Two Steps: Antigen Presentation during Second Encounter Is Decisive

The differentiation of CD4 T cells into Th1 and Th2 cells in vivo is difficult to analyze since it is influenced by many factors such as genetic background of the mice, nature of antigen, and adjuvant. In this study, we used a well-established model, which allows inducing Th1 or Th2 cells simply by low (LD, 10⁵) or high dose (HD, 10⁹) injection of sheep red blood cells (SRBC) into C57BL/6 mice. Signature cytokine mRNA expression was determined in specific splenic compartments after isolation by laser-microdissection. LD immunization with SRBC induced T cell proliferation in the splenic T cell zone but no Th1 differentiation. A second administration of SRBC into the skin rapidly generated Th1 cells. In contrast, HD immunization with SRBC induced both T cell proliferation and immediate Th2 differentiation. In addition, splenic marginal zone and B cell zone were activated indicating B cells as antigen presenting cells. Interestingly, disruption of the splenic architecture, in particular of the marginal zone, abolished Th2 differentiation and led to the generation of Th1 cells, confirming that antigen presentation by B cells directs Th2 polarization. Only in its absence Th1 cells develop. Therefore, B cells might be promising targets in order to therapeutically modulate the T cell response.     

Studies of the immunological capacity of germ-free mouse radiation chimeras: I. Chimerism and humoral immune response

The genetic origin of both the functional lymphoid cell and progenitor cell populations of germ-free mouse radiation chimeras was assessed by indirect immunofluorescence (IIF), anti-H-2 cytotoxicity, and survival of lethally x-irradiated secondary recipients of chimera cell populations. These studies demonstrated that germ free C3H/He mice given 1000 R and 10⁷ DBA/2 bone marrow cells express H-2 antigens on their lymphoid and bone marrow cell populations characteristic of the DBA/2 donor. These cells persist for at least 14 months postirradiation and bone marrow transplantation. However, these allogeneic mouse radiation chimeras have a reduced humoral immune response to sheep erythrocytes (SRBC). This decreased humoral immune capacity as assessed by kinetic studies of the spleen plaque-forming cell (PFC) response is present throughout the life span of the chimera. The γ₁ PFC response shows extreme depression. The reduced humoral immune responsiveness to the thymusdependent SRBC antigen is considered to be due to the absence or malfunctioning of a thymocyte population.     

Different effects of the capsular polysaccharide of Klebsiella pneumoniae on the functions of various subpopulations of B cells in the immune response of mice to T-dependent antigen.

Using the capsular polysaccharide of Klebsiella pneumoniae (CPS-K) as a polyclonal B-cell activator (PBA) and sheep red blood cells (SRBC) as a T-dependent antigen, we studied the effects of PBA on the functions of various subpopulations of B cells in the immune response of mice to T-dependent antigen. Antibody-forming cells (AFC) of IgM and IgG types were estimated as anti-SRBC direct and indirect plaque-forming cells (PFC), and the B cells with precursor activities involving generation of AFC and supplementing new B cells as rosette-forming cells (RFC) of the B-cell type. Stimulation of normal mice by CPS-K caused a definite increase in the number of direct PFC but not in that of indirect PFC and RFC in the spleens. The responsiveness of spleen cells of CPS-K-treated mice to generate PFC and RFC responses to a subsequent injection of SRBC was lower than that of CPS-K-untreated normal mice. In this case, the responsiveness to generate RFC and indirect PFC was inhibited more strongly by CPS-K than that to generate direct PFC. When CPS-K was injected into normal mice simultaneously with SRBC, CPS-K never decreased but increased the levels of PFC and RFC responses to SRBC. In the spleens of SRBC-primed mice, the number of RFC was markedly decreased following injection of CPS-K, the number of direct PFC was increased only slightly and the number of indirect PFC was increased very slightly. The responsiveness of spleen cells of these CPS-K-treated SRBC-primed mice to generate secondary PFC and RFC responses to a subsequent injection of SRBC was much lower than that of CPS-K-untreated SRBC-primed mice. In this case, the responsiveness to generate the secondary RFC and indirect PFC responses was more strongly inhibited by CPS-K than that to generate the secondary direct PFC response. When CPS-K was injected into SRBC-primed mice simultaneously with the secondary injection of SRBC, there were marked decreases in the level of the secondary RFC response and slight decreases in that of the secondary indirect PFC response, but little change in that of the secondary direct PFC response. From these results it has been concluded that CPS-K provides the positive signal (the minor action) and the negative signal (the major action) to various subpopulations of B cells functioning at various stages of the immune response to T-dependent antigen in different ways, and acts to regulate the levels of B-cell responses to the antigen-mediated positive signal.     

Formation of heterophile antibodies by human tonsilar lymphocytes: II. In vitro stimulation with allogeneic cells

Short-term cultures of human tonsilar lymphocytes (HTL), 5 × 10⁶ cells/culture, in medium RPMI 1640 supplemented with human group AB serum were studied for the production of plaque-forming cells (PFC) against sheep (SRBC) and bovine (BRBC) red blood cells following in vitro stimulation by various allogeneic lymphoid cells. Of 55 HTL specimens examined, 48 produced a significant number (50–300/culture) of PFC against SRBC and/or BRBC following the in vitro stimulation. The optimal doses of the stimulator HTL and peripheral blood lymphocytes (PBL) were 10⁷ and 5 × 10⁶/culture, respectively. After the stimulation, PFC appeared in significant numbers on the third day, reached the peak number on the sixth day, and decreased sharply in number thereafter. Removal of E-rosetting cells from both stimulator and responder populations abolished the PFC formation. PFC formation against SRBC was inhibited by solubilized Forssman antigen, while PFC formation against BRBC was inhibited strongly by Hanganutziu-Deicher antigen, hardly by Paul-Bunnell antigen and not at all by Forssman antigen. Supernatants of mixed lymphocyte culture of PBL were shown to enhance PFC formation of HTL cultures stimulated by allogeneic lymphocytes. The results of this study indicated that in vivo primed B cells of the HTL were triggered in vitro by allogeneic stimulation for the heterophile antibody formation. Since these antibodies are apparently directed against Forssman and Hanganutziu-Deicher antigens, the “allo” nature of these antigens as well as their relationship to the previously described heterophile transplantation antigens have to be clarified.     

In Vivo Production of Various Cytokines in Splenocytes of Sheep Erythrocyte-Immunized Mice after Intravenous Administration of Bacterial Lipid A

The effects of an intravenous administration of lipid A from Salmonella minnesota R595 lipopolysaccharide on the in vivo production of interleukin-2 (IL-2), IL-4, IL-5 and IL-6 in the spleens of mice intravenously immunized with sheep red blood cell (SRBC) antigen were investigated. The increased number of antigen-specific IgM antibody-producing cells and the titer of the IgM serum antibody were measured using the plaque-forming cell (PFC) assay and an enzyme-linked immunosorbent assay (ELISA). Simultaneous injections of SRBC antigen and lipid A adjuvant enhanced IgM-PFC number on days 3 and 4 and the serum IgM titer on days 4 and 5 after the immunization. We found that the enhanced IL-4 and IL-5 levels correlated with the PFC number and IgM titer. When lipid A was injected intravenously 2 days after immunization with SRBC, the PFC number in lipid A-treated groups were similar to those in controls 3 and 4 days after the immunization. However, it was found that a twofold increase in the IgM titer in serum was induced by lipid A 5 days after immunization. In relation to this increase, lipid A stimulated the production of only IL-5 among the cytokines tested.     

Impaired Antigen Specific Responses and Enhanced Polyclonal Stimulation in Mice Infected with Ehrlichia muris

The immune status of BALB/c mice infected by intraperitoneal inoculation with Ehrlichia muris was examined. The level of E. muris infection in both peritoneal cavity and spleen was greatest at day 10 postinoculation (PI). Thereafter, the infection level was dramatically reduced while the organism persisted for up to 400 days PI. The greatest intraperitoneal infiltration of leukocytes, splenomegaly, and leukocytosis were observed on days 10, 15, and 20 PI, respectively. Infected mice developed marked hypergammaglobulinemia of IgG and IgM that peaked at day 20 PI; however, IgA plummeted at day 15 PI. Of IgG, G2a and G3 increased while G1 and G2b remained constant. Despite hypergammaglobulinemia, both IgG and IgM antibody titers against E. muris were very low throughout the 30-day study. Antibody development and plaque-forming cells against sheep red blood cells (SRBC) were abolished when the antigen was inoculated on day 10 PI. IgM antibody development against SRBC was more severely inhibited than IgG antibody development. However, when mice were immunized with SRBC prior to E. muris infection, antibody development against SRBC was not reduced. Delayed type hypersensitivity reaction to dinitrofluorobenzene was also maximally inhibited when the antigen was administered on day 10 PI. The IFN-γ level in the blood was maximal at day 10 PI. These results indicate that although the vigorous polyclonal activation and protective IFN-γ responses occurred by day 10 PI—which cleared most of the ehrlichial infection—antigen-specific immune stimulation was impaired primarily at the level of antigen-priming at peak parasitemia.     

B-L antigens (Class II) of the chicken major histocompatibility complex control T-B cell interaction

The detailed study of the genetic control of T-B cell interactions in the chicken has been hampered by the lack of defined major histocompatibility complex (MHC) recombinant chicken lines. In the present study we have used some recently described MHC recombinant chicken lines separating regions encoding antigens that are homologous to class I and class II antigens of mammals in adoptive bursa cell transfer experiments, in which bursa cells from newly hatched chicks were transplanted into cyclophosphamide (Cy)-treated chicks. Subsequent immunizations of the recipients with a thymus-dependent antigen (SRBC) and a thymus-independent antigen (Brucella abortus) showed that the generation of germinal centers in the spleen and the production of antibodies to SRBC required identity between donor and recipient class II antigens (B-L antigens), whereas response to Brucella antigen did not require identity at any of the known MHC loci of the chicken. The results thus reveal that also in the chicken class II (B-L) region genes encode cell-surface glycoproteins that serve as restriction elements in T-B cell cooperation.This work has been presented in part at the Ninth International Congress of the Transplantation Society (Vainio et al. 1983a).     

Erythrocyte antigen: isolation, biochemical and immunologic properties]

The authors suggest a simple method of obtaining erythrocytic antigen in considerable amounts. This antigen is of stromal origin, contains from 10 to 20% protein, and is relatively homogenous. With the concentration of from 1 to 50 microgram by protein the preparation represents a transparent solution; with greater concentrations the antigen is white, turbid, but is well dissolved and convenient for administration to the animals. In case of a single administration without any adjuvants the antigen is highly immunogenic in low doses by protein. To the optimal immunizing dose of erythrocytes (5 X 10(8)) correspond about 100 microgram of the antigen by protein. The primary response to the antigen is similar to the response to sheep red blood cells (SRBC). It is exceedingly effective for the formation of immunological memory. The level of secondary responses in the adoptive transfer to all the EAG doses always exceeded the secondary response to SRBC. By adding EAG into agar during the local hemolysis in gel test determined the avidity of the antibodies synthesized at various periods of the immune response to SRBC.     

Effects of microwave exposure on the hamster immune system. IV. Spleen cell IgM hemolytic plaque formation

Microwave exposure has been reported to affect various components of the immune system. In this study, we examined the effect of a single whole-body exposure of hamsters to microwave (mw) energy (2.45 GHz; 5-25 mW/cm2; 1 h) on the IgM antibody (Ab) response of spleen cells to sheep red blood cells (SRBC). MW-exposed, sham-exposed, and cage-control hamsters were immunized with SRBC and plaque-forming cells (PFC) in spleens assayed using the direct hemolytic plaque assay. In cage-control hamsters the Ab response was highest between days 4 and 5, returning to baseline by day 9. MW exposure (25 mW/cm2 for 1 h) significantly augmented PFC response only on days 4 and 5 postimmunization, causing approximately a 4.3- and 3.5-fold increase over controls, respectively. Exposure to 15 mW/cm2 caused a lesser, but significant increase in PFC. Exposure to intensities below 15 mW/cm2 for 1 h did not produce any increase in Ab response. Immunization with different concentrations of SRBC following 1 h of 25 mW/cm2 MW exposure revealed a stimulation in PFC at all concentrations ranging from 5 X 10(7) to 5 X 10(8) SRBC. Pretreatment of hamsters with MW radiation prior to immunization showed that the animals retained an increased sensitivity to SRBC for as long as 4 days after MW exposure. In contrast, exposure of hamsters to MW energy on different days after immunization showed an effect of the PFC response only if given between 0 and 1 day after immunization. These results suggest that MW exposure augments the primary IgM response to SRBC by affecting some early event in the immune response process. The various possible explanations for this phenomenon are discussed.     

The immunoregulatory role of bone marrow. I. Suppression of the induction of antibody responses to T-dependent and T-independent antigens by cells in the bone marrow.

Bone marrow cells (BMC) from normal mice suppressed the in vitro IgM, but not the IgG, antibody (Ab) response of spleen cells. BMC were inhibitory only when added during the first 24 hr of culture, and inhibition was not due to an induced shift in the kinetics of the response. Addition of specifically activated T cells or nonspecific T-cell-replacing factors to normal or T-depleted spleen cell cultures did not abrogate suppression while the response to the T-independent antigen DNP-polymerized flagellin or lipopolysaccharide was also suppressed. BMC did not inhibit background Ab synthesis by normal or primed cells in the absence of antigen and did not inhibit, but stimulated, DNA synthesis in normal spleen cell cultures. In addition, high-avidity Ab synthesis was preferentially suppressed. A possible role for the bone marrow suppressor cell in the induction of B cell tolerance is discussed.     

Demonstration of the common precursor for production of IgM and IgG antibodies

In experiments, in which a limited number of isologous spleen cells with sheep red blood cells (SRBC) were transferred to the lethally irradiated recipients, the foci were detected on the replicas by two methods, which enabled the detection of IgM-and IgG-producing cells. By both methods only foci containing IgM were found shortly after transfer; later, on day 6 after transfer, foci containing IgG cells were detected (approximately in 10% of IgM foci). Almost all these IgG-containing foci matched with IgM foci (90% on day 6). These results suggest that during the multiplication of immunologically activated (progenitor) cells, a gene switch occurred. The cells may then be able to be transformed by a second antigenic stimulus either into IgM, or later, after approximately 6–7 multiplications, when the switch in progenitor cells occurred, into IgG-forming cells.     

An H-11-linked gene has a parallel effect on Leishmania major and L. donovani infections in mice

The courses of visceral infection following intravenous injection of Leishmania donovani amastigotes, or lesion growth following subcutaneous injection of L. major promastigotes, were examined in B10.129(IOM) (H-2 ^b, H-11 ^b) mice and compared with disease profiles observed in congenic C57BL/10ScSn(=B10) (H-2 ^b, H-11 ^a) and B10.D2/n (H-2 ^d, H-11 ^a) mice, and in BALB/mice. Possession of alternative alleles at H-11 and closely linked loci transformed the normal curing/healing phenotype of B 10 mice into a characteristically different noncuring/nonhealing phenotype affecting both visceral and subcutaneous infections in B10.129(10M) mice. In reciprocal radiation bone marrow chimeras made between the congenic B10 and B10.129(10M) strains, both cure and noncure phenotypes were transferable with the donor hematopoietic system. Although it was possible to demonstrate transfer of suppression with T-enriched spleen cells from day 61 L. donovani-infected B10.129(10M) donor mice into 550 rad syngeneic recipients, the pretreatment of mice with sublethal irradiation did not, as in the earlier studies of Scl-controlled L. major nonhealing or H-2-controlled L. donovani noncure phenotypes, have a clear or consistent prophylactic effect. Together with the progressive disease profile observed even for L. donovani at low parasite doses this suggests that, despite their ability to develop initial delayed-type hypersensitivity reactions to parasite antigen early in L. major infection, B10.129(10M) mice possess some inherent defect in ability to mount a cell-mediated response effective at the level of macrophage antileishmanial activity in vivo even when suppressor T cells are not generated. Further elucidation of this characteristically different noncuring/nonhealing phenotype may provide important insight into common events involved in the development of the cell-mediated immune response to both visceral and subcutaneous forms of leishmaniasis.     

In vitro allotype suppression of spleen cells from immunized rabbits

We tested whether rabbit immune lymphocytes could be suppressed by anti-allotype antibody (Ab) in vitro as shown for normal lymphocytes. Spleen cells (SpC) from rabbits heterozygous at the b locus (b⁴b⁵) of immunoglobulin (Ig) κ chains were treated with IgG preparations of anti-b4 or anti-b5 Ab in vitro for 24 hr (day 1). After this treatment, the SpC were washed and recultured in medium to day 5. The secreted b4- and b5-Ig were quantitated by a radioimmunoassay. SpC from rabbits injected once with sheep red blood cells (SRBC) were allotype-suppressed. Thus, these SpC treated with anti-b4 Ab secreted normal amounts of b5-Ig but secreted much lower amounts of b4-Ig. Similarly, SpC treated with anti-b5 Ab secreted normal amounts of b4-Ig but secreted no detectable b5-Ig. In contrast, SpC from rabbits injected several times with SRBC (hyperimmunized) could not be allotype-suppressed. Hence, the susceptibility of primary immune cells and the resistance of hyperimmune cells to suppression appear to depend on the stage of B-lymphocyte differentiation, presumably because of loss of surface Ig or perhaps because of other changes in the cells as they differentiate during the immune response.