Cytodynamics of the immune response in two lines of mice genetically selected for "high" and "low" antibody synthesis.

Two lines of mice have been separated by selective breeding for the character "agglutinin production to heterologous erythrocytes." Around the 18th generation of selection the two lines could be considered as homozygous for the character investigated. This trait is under the control of a group of additive genes. The interline difference in the production of anti-SE agglutinins was verified for the range of antigen doses from subimmunogenic to maximal. After intravenous immunization with an optimal dose of SE, the duration of the exponential rise in serum antibody was 4-5 days in both lines. At this time most of the interline difference in responsiveness is already expressed. A cytodynamic study carried out in terms of plaque-forming cells (PFC) and rosette-forming cells (RFC) in the spleen during the exponential phase showed that the principal interline difference is found in the doubling time of cells engaged in the immune response. More precise cytodynamic analysis made in terms of RFC showed that the doubling time of RFC is 9 hr in high responder and 16 hr in low responder mice. The duration of the exponential rise and the number of target cells stimulated by antigen is the same in both lines. The interline difference at the end of the exponential rise (4 days postimmunization) is larger in terms of serum antibody (30-40-fold) than in terms of PFC or RFC (20- and 11-fold, respectively). A morphological study of RFC in nonimmunized mice showed that about 90% of rosettes were formed by small lymphocytes in both lines. The remainder were medium-sized lymphocytes. At the peak of the cellular response the RFC have differentiated into large lymphocytes, blast cells, and plasma cells. The contribution of plasma cells to RFC is much greater in the high than in the low line. The cytodynamic and morphologic results presented in this article are compatible with the hypothesis that the group of genes segregated in each line during the selective breeding control and regulate the rate of multiplication and differentiation of the antibody-producing cells.

Serum concentrations and allotypes of immunoglobulins in two lines of mice genetically selected for "high" or "low" antibody synthesis.

Random-bred Swiss mice were selectively bred for 16 generations; selection was based on their agglutinin response to sheep and pigeon erythrocytes to produce a high and a low responder line. The serum levels of individual immunoglobulins differed significantly in these two lines before immunization. The differences in the levels of immunoglobulins were much more marked after immunization with pigeon or sheep erythrocytes. Greater differences between the two lines were noted in IgM and IgG levels than in IgA. Another remarkable finding was the presence of different immunoglobulin phenotypes in the two lines. The high responders were homozygous or heterozygous for heavy-chain linkage groups found separately in the prototype BALB/c and C57BL inbred strains. The low responders were homozygous for a heavy-chain linkage group not present in bred mice in the United States, but observed as a recombinant type among wild mice probably representing a crossover between the heavy-chain linkage groups of the prototype DBA/2 and NH inbred mice.

Genetic factors controlling anti-sheep erythrocyte antibody response and immunoglobulin synthesis in backcross and F2 progeny of mice genetically selected for "high" or "low" antibody synthesis.

Agglutinin responses to sheep erythrocytes and immunoglobulin heavy chain phenotypes determined in F(1), F(2), and backcross progeny of mice genetically selected for high and low antibody synthesis indicated that an immune response gene for sheep erythrocytes is linked to the immunoglobulin heavy chain allotype. Mice homozygous for the phenotype of the high line had significantly higher titers than mice homozygous for the phenotype of the low line. An association was also observed in some progeny of the backcross of the F(1) generation with the low line. However, the control of the immune response was clearly multigenic since heterozygous mice of the same phenotype (2/3, 5) resulting from the two backcrosses (high and low) had very different immune responses. Immunoglobulin levels in the same progeny showed no linkage to the immunoglobulin allotype but a rather simple pattern of inheritance.

Genetic control of macrophage functions. I. Polygenic regulation of phagocytosis stimulation produced by Glyceryl Trioleate.

The phagocytic index K, established from the rate of blood clearance of colloidal carbon, measures the phagocytic activity of RE macrophages in contact with the circulating blood. The intravenous injection of glyceryl trioleate (triolein) produces a marked stimulation of the phagocytic activity of RE macrophages. This response is higher in the female than in the male mice. The phenotypic character "responsiveness of macrophage to triolein" presents large individual variants in population of random bred albinos mice. This character is submitted to polygenic regulation. Starting from a foundation population of 25 males and 25 females random bred albinos, mice, two lines were separated by selective breeding for the character "responsiveness to triolein": a "high" responder line, KTH, and a "low" responder line, KTL. After 26 consecutive generations of selective breeding, KTH mice present a very high response to triolein while KTL mice are almost irresponsive. The heritability of this character (h2) calculated from the interline divergence is of 12% plus or minus 1. This value of h2 indicates that the character investigated is determined by the cumulative effect of a group of about 27 independently segregating loci. The distribution of the character in (KTH plus KTL)F1 and their backcrosses with parental lines suggests that low responsiveness is dominant over high responsiveness. The genetic regulation of responsiveness to triolein is independent from the dose administered. These results are discussed in relation to the importance of genetic factors controlling macrophage functions involved in lipid metabolism and in the specific mechanisms of immunity.

[Transrectal ultrasound and biopsy of the prostate]. / Echographie et biopsies de prostate.

This review describes the transrectal ultrasound (TRUS) features of prostate cancer (PC), discusses the role of TRUS in the detection of PC and defines the modalities of biopsies in patients with suspected PC, particularly concerning prevention of complications, the number of biopsies and the biopsy schemes ensuring an optimal cancer detection rate. TRUS alone has limited potential to identify PC because of frequent multifocality of cancer within the prostate, the variable sonographic appearance of prostatic tumors, the poor specificity of focal US abnormalities, and the substantial percentage of isoechoic PC. Over the past decade, the sextant biopsy technique has emerged as the standard of care in the detection of PC. However, limitations in cancer detection have been appreciated, particularly a false-negative rate approaching 20%. This high failure rate has led investigators to refine biopsy techniques to improve cancer detection and to increase the total number of cores. Currently, recommendations include increasing the biopsy number to a minimum of 10-12 cores, including sampling of the lateral prostate. Refinements in imaging technologies (power Doppler sonography, microbubble intravenous sonographic contrast agents, and MR spectroscopy or dynamic contrast MR imaging) should eventually improve targeting of prostate needle biopsy and reduce false-negative biopsies.

[Prostatic neoplasms: clinical and biological aspects, histopathologic patterns]. / Cancer de la prostate: les aspects cliniques, biologiques et histopathologiques utiles au radiologue.

Medical imaging has an important role in the diagnosis and treatment options of prostate cancer (TRUS guided biopsies, MRI). The knowledge of the different types of cancers, their preferred topography, imaging features, extension pattern, and also the important items that may help the surgical procedure (or any other treatment) are as many crucial key points for optimal management of patients.

Comparison of 7,12-dimethylbenz(a)anthracene-DNA adduction in the epidermis of two lines of mice selected for resistance (CAR-R) or susceptibility (CAR-S) to skin carcinogenesis.

Two lines of mice were produced by bidirectional selective breeding: one resistant (CAR-R) and one susceptible (CAR-S) to two-stage skin carcinogenesis by dimethylbenz(a)anthracene and 12-O-tetradecanoyl-phorbol-13-acetate. The dimethylbenz(a)anthracene-DNA adduct formation was compared in the two lines by a postlabeling procedure so as to determine whether the striking interline difference observed as to tumor incidence could (in part) be due to differences in the formation of DNA-reactive metabolites. Results show that qualitatively, adduct profiles in CAR-R and CAR-S epidermis are similar. Quantitatively, the total binding level is slightly higher in CAR-S versus CAR-R mice during the 30-day follow-up. However, these minor differences do not increase in function of the response to selection observed through three consecutive generations. A 2- or 4-week promotion with 12-O-tetradecanoylphorbol-13-acetate enhances the decrease of adduct level in the two lines. This effect is somewhat more pronounced in CAR-S mice. Results strongly suggest that the expression of the genes responsible for CAR-R/CAR-S phenotypic difference affects mainly the postinitiation stages.

Genes responsible for quantitative regulation of antibody production.

Evidence is first presented demonstrating that the individual capacity for antibody responsiveness has an inheritable component. The main evidence consists of spontaneous mutations causing either immunodeficiency or predisposition to autoimmunity in human and animals, and the involvement of some obvious candidate genes (in particular those belonging to the highly polymorphic histocompatibility and Igh loci), extensively analyzed in many mouse strain combinations. One finding constantly emerging from these studies is that single gene expression depends on environmental effects, lowering the genotype/phenotype correlation, but also on multigenic interactions appearing as background effects. The models available for the analysis of this multigenic regulation are discussed with special emphasis on the high and low antibody responder mice produced for this purpose by bidirectional selective breeding. The major advantage of this model is that the interline difference is huge and multispecifically expressed. The second part of the review presents the recent results on positional mapping of genes with immunomodulatory effects in this model and in one appropriate recombinant congenic strain series. This in vivo genetic dissection of antibody responsiveness discriminated the involvement of candidate genes and suggested that unsuspected genes might be identified by means of this wide open search.

Genetic control of immune responsiveness, aging and tumor incidence.

Age-related alterations of the immune system affect both antibody and cell-mediated immune responses, T-cell responses being more severely affected than B-cell responses. Within the T-cell population, aging leads to replacement of virgin by memory cells and to accumulation of cells with signal transduction defects. Changes in T-cell subsets and in cytokine production profiles may produce suitable conditions for T-cell-mediated disregulation of antibody responses characterized by the production of low affinity and self-reactive antibodies. Also B-cells exhibit intrinsic defects and natural killer (NK) cell activity a profound loss in old mice. Whether age-related immune disfunctions influence life span and tumor incidence has been examined in mice genetically selected for high or low antibody responsiveness. It has been found that genetic selection of vigorous antibody responses in most cases produces mice with longer life span and lower lymphoma incidence. Moreover, the results of genetic segregation experiments indicate that antibody responsiveness and life span are polygenic traits regulated by a small number of the same or closely linked loci. Mice genetically selected for high or low mitotic responsiveness to PHA exhibit low or high tumor incidence, respectively, but no difference in life span, suggesting that T-cell activity is restricted to immune surveillance of neoplastic transformation. Studies on mice genetically selected for resistance or sensitivity to chemical carcinogenesis have uncovered loci that control both resistance to tumor induction and longevity while have no effects on immunity and disease incidence. Thus, the relative role of the immune system in conditioning the duration and the biological quality of life remains to be determined.

Quantitative effect of H-2-linked gene(s) on antibody response to human gamma-globulin.

H-2-linked gene(s) have been found to play a role in the quantitative regulation of response to human gamma-globulin (HGG) in mice selected for high or low antibody responsiveness to sheep erythrocytes. Unexpectedly, in a random genetically heterogeneous population of F2 interline hybrids, the gene(s) linked to the H-2 phenotype of H mice has a "low" effect, and the gene(s) linked to the H-2 phenotype of L mice a "high" effect on the magnitude of antibody response to HGG. In H and L mice, the non-specific polygenic control of antibody responsiveness is able to compensate/counteract the inverse effect of HGG-specific H-2-linked gene(s) since the usual interline difference is observed.

Dose-dependent efficacy of vaccination against K. pneumoniae in high and low antibody responder lines of mice.

Innate and acquired resistance to Klebsiella pneumoniae infection were investigated in high (HI) and low (LI) antibody responder lines of mice. The two lines were very susceptible to infection since even small inoculum doses of a virulent strain provoked a 100% mortality within a few days. However the mean survival time was significantly longer in LI than in HI. (HI X LI) F1 hybrids were more resistant than both parental lines. Immunization with heat killed K. pneumoniae was able to confer full protection on the mice in the two lines. However there was a large difference in the number of killed bacteria required to induce the protective effect in HI and in LI mice. The dose-effect relationship for protection correlated with that of antibody production. The protective role of antibodies was confirmed by the survival of HI and LI mice, when antibodies were passively given prior to lethal challenge. The results are in agreement with the fact already demonstrated, that the defect of LI mice in antibody responsiveness is a quantitative one. Therefore a satisfactory immune protection against K. pneumoniae could be obtained in LI mice by adapting the vaccination procedure.

Evaluation of T helper function in lines of mice selected for high or low antibody production: quantitative inhibition of immune responses by anti-L3T4+ monoclonal antibody.

The potentialities of T helper cell compartment were compared in lines of mice selected for high or low Ab production against heterologous erythrocytes (H1 and L1 mice) by investigating the "in vivo" and "in vitro" modulation of immune responses by GK 1-5 anti-L3T4+ mAb. FACS analysis showed a frequency of L3T4+ cells similar in non-immunized mice of both lines. However, LI mice were more susceptible to inhibition of the IgG Ab response to SE when injected GK 1-5 prior to immunization. The "in vitro" proliferation of T cells specific for HEL was higher in HI than in LI LN cultures, and a higher GK 1-5 mAb concentration had to be applied to HI cultures in order to produce the inhibitory effect. In contrast, during MLR, the capacity for T proliferation was similar in HI and LI cultures stimulated by a common F1 target. This allo-Ag-induced proliferation was inhibited at similar GK 1-5 mAb concentrations in the two lines. These results demonstrate that there is no intrinsic L3T4+ cell deficiency in LI mice. Differences in GK 1-5 mAb required for inhibition of responses to Ag (other than allo-Ag) in HI and LI mice are mainly due to different macrophage T cell triggering.

Genetic regulation of the specific and non-specific component of immunity.

Bi-directional selective breeding for antibody (Ab) responsiveness to heterologous erythrocytes (Selection I) produced a high (H) and a low (L) responder line of mice which were also remarkably separated for Ab responses to many unrelated natural antigens (Ags) such as heterologous proteins, viruses, bacteria, parasites and haptens carried by these immunogens. The character "quantitative Ab responsiveness" is controlled by several independently segregating loci (polygenic regulation). The major genetic modification is produced at the level of macrophage activities. The Ag is slowly catabolized and persists for a long time on the macrophage membrane of the H line, whereas it is rapidly destroyed in L line macrophages. The bactericidal and bacteriostatic activity of the macrophage is also strong in the L line and weak in the H line. The opposite genetic regulation of Ab responsiveness and macrophage activity is a fundamental phenomenon for understanding natural and vaccination-induced anti-infectious immunity. The L line is more resistant than the H line against the infections due to intracellular microorganisms (Salmonellae, Yersinia, Mycobacteria, Brucellae, Leishmania) where the macrophage plays the dominant defensive barrier. The H line is more resistant than the L line to the extracellular microorganisms which are efficiently counteracted by a strong antibody response (Pneumococcus, Klebsiella, Plasmodia, Trypanosoma). The intensity of T cell-mediated immunity as measured by delayed type hypersensitivity, which is independent of the genetic regulation of antibody responsiveness, is correlated with the degree of nonspecific inflammation produced at the site of the reaction by the Ag injection in non-sensitized mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Inversion of genetic predisposition to carcinogenesis in liver of two lines of mice selected for resistance (Car-R) or susceptibility (Car-S) to skin carcinogenesis.

Two lines of mice, one resistant (Car-R) and one susceptible (Car-S) to skin carcinogenesis, were produced by bi-directional selective breeding. To see whether the characteristics of susceptibility or resistance to tumorigenesis were also expressed in the liver and lung, the two lines were submitted comparatively to treatment with 5,9-dimethyl dibenzo[c,g]carbazole (DiMeDBC), a potent hepatocarcinogenic derivative of the ubiquitous heterocyclic carcinogenic pollutant, 7H-dibenzo[c,g]-carbazole (DBC). An inversion of genetic predisposition to carcinogenesis in liver was observed. Car-R animals displayed rapid tumorigenesis in 100% of cases while Car-S mice were remarkably less sensitive, showing a 4-fold lower mean tumor multiplicity and a 4-month longer latency time. In parallel adduct formation by DiMeDBC and DBC in liver DNA was analyzed by the 32P-postlabeling method, showing a remarkably higher level in Car-R mice than in Car-S animals. These data indicate that tissue-specific sensibility in carcinogenesis may involve gene expression at various levels.

Low antibody responsiveness is found to be associated with resistance to chemical skin tumorigenesis in several lines of Biozzi mice.

High and low antibody responder lines of mice from Selections I, III and G were assayed for two-step skin tumorigenesis using a protocol consisting in initiation with 7,12-dimethylbenz[a]anthracene (DMBA) and promotion with 12-O-tetradecanoylphorbol-13-acetate (TPA). Concordant results were obtained in the three selections: low antibody responder mice were shown to be significantly more resistant to tumor induction than the high responder counterparts. The difference was observed for all parameters: kinetics and percentages of tumor incidence and tumor multiplicity. The three bidirectional selective breeding experiments differed in several respects namely, the origin of the foundation populations, the antigens and immunization protocols used during the selection, as well as the breeding unit environments. Therefore, the consistent results relative to tumorigenesis strongly suggest that some of the alleles relevant to multispecific 'low' antibody production could contribute to the resistance to cutaneous chemical tumorigenesis.

Mice selected for low and high blood magnesium levels: a new model for stress studies.

Extra- and intracellular magnesium levels have previously been shown to be genetically controlled in humans and in the mouse. To further study this genetic regulation, mice were selected from a heterogeneous population, for low (MGL mice) and high (MGH mice) red blood cell (RBC) magnesium values. These values diverged rapidly in the two strains, to reach a stable difference between the 14th and 18th generations. MGL mice also exhibited significantly lower plasma, kidney, and skull bone magnesium contents and higher urinary magnesium excretion and total brain weights. Moreover, in stressful conditions, MGL mice displayed a more aggressive behavior that the control MGH strain. Altogether, MGL mice showed a more restless behavior, a higher rectal temperature, and much higher brain (+17%) and urine (+200%) noradrenaline levels than the MGH animals. These strains, thus, constitute a new animal model for the study of magnesium metabolism and its relationships with catecholamines, stress sensitivity, and aggressive behavior.

Isotypic distribution of antibody responses in lines of mice selected for high or low immunoresponsiveness.

1. The isotype distribution of antibody (Ab) responses to Salmonella antigens (Ag) was investigated in high (H) and low (L) Ab responder lines of mice from Selections III and IV carried out for responsiveness to flagellar (f) and somatic (s) Ag, respectively. 2. Primary immunization resulted in higher Ab titers of all isotypes in response to both Ag in H mice from both selections and was confirmed after booster injections. The interline difference (H-L) in response to the distinct isotypes ranged from 3.0 to 7.0 log2 to Ag f in Selection III and from 2.0 to 5.1 log2 to Ag s in Selection IV. 3. Comparison of isotype production to 3 Ag in Selections I, II, III and IV demonstrated that: 1) the highest responses in all mice are those against the selection Ag, 2) the isotypic pattern depends on both the Ag injected and the host's genetic constitution, and 3) the presence or lack of a multispecific effect is not due to isotype-restricted regulation.

Genetic regulation of macrophage functions.

Normal phagocytic function is genetically determined but maintained in a rather narrow range of variation. Phagocytosis stimulation induced by different agents is variable according to species, strains or individuals. Variation is environmental, to a great extent, but has also a genetic component which differs in each case. Selective breeding for macrophage responsiveness to triolein stimulation was successful. However, the relevant genes have only a small effect on antibody synthesis. Macrophages of mice selected for high and low antibody synthesis have a similar phagocytic function but their capacities of antigen processing are quite different.