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At least 361 records · Page 20Linked to original sources
PubMed1976

Humoral immunity in aged mice. II. Increased suppressor T cell activity in immunologically deficient old mice.

Mixed cultures of DNP-primed spleen cells from old and young BC3F1 mice in diffusion chambers yielded significantly fewer secondary PFC than expected from the numbers of PFC found when young and old spleen cells were cultured alone. There was a negative correlation between the log of the number of PFC found in cultures of old spleen cells alone and the degree of immunosuppression exerted by the cells. The immunosuppressive effect was abolished by pretreatment of the old spleen cells with anti-theta serum and complement. Thus, the effect was attributed to the presence of large numbers of suppressor T cells in the spleen of primed old mice. No suppression was found in mixed cultures of spleen cells from old unimmunized mice and young primed mice.

Aging↗
PubMed1994

[Experimental evaluation of antibiotics as immunomodulators].

Since the pioneer work by Metchnikoff, the goal of cooperation between therapeutics and the host defence system (HDS) has been sought after. This area of research received less attention after the introduction of antibiotics. Although, the predictive efficacy of antibacterial agents (ABA) is still evaluated in terms of MICs, MBCs, and pharmacokinetics, much evidence derived from clinical studies underlines the need for synergy between HDS and these drugs to obtain optimal therapeutic efficacy. The analysis of the immunomodifying properties of ABA has come under intense study. The majority of ABA does not substantially affect the functioning of the immune system at least in vivo, despite in-vitro observations of enhancement/inhibition of various immune parameters by some cephalosporins, macrolides, cyclins, aminoglycosides, etc. By contrast, chloramphenicol, sulphonamides and various beta-lactams may be responsible for drug-induced neutropenia whereas macrolides and quinolones, due to their high phagocytic uptake, synergize with phagocytes to destroy intracellular pathogens. Recently, the concept of Biological Response Modifier (BRM)-antibiotics has come under the limelight with the introduction of cefodizime, a new parenteral cephalosporin, which seems to be endowed with immunomodulating properties. This latter aspect has been demonstrated in vitro (potentiation of the phagocyte antimicrobial activity), ex vivo in immunocompromised animals and humans (restoration of various immune parameters) and in vivo (infection models using both sensitive and resistant species). Although the underlying mechanism has not been elucitated, the chemical structure responsible for this BRM activity has been recognized as the thio-thiazolyl moiety at C3 position of the cephem nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗
PubMed1994

[Immune response to antibiotics in patients with secondary immunodeficiencies].

A biological response modifier (BRM) has been defined as an agent able to modulate effector mechanisms or mediators of host defence. Some antibiotic molecules have been shown to display a BRM like activity, being able to enhance immune responses (certain cephalosporins), to synergize with the immune effectors (macrolides, quinolones) or alternatively, to depress immune functions (tetracyclines or antimycotic drugs). The BRM-like activity of different antibiotic molecules has been widely reported in in vitro studies as well as ex vivo in experimental animal models. Only recently some Authors have approached the problem by investigating whether the in vivo administration of antibiotic was able to affect different immune effector functions, either in healthy subjects or in patients. The main question in the field is the possible clinical impact of the connections between antibiotics and the immune system, particularly in subjects with acquired immunodeficiency in whom the impairment of the immune responses leads to increased susceptibility to infectious processes. Ex vivo data seem to suggest that cefodizime, one of the newest third-generation cephalosporins, is able to enhance phagocyte and mononuclear cell functions in healthy volunteers, thus confirming the possibility of combining an antibacterial efficacy with the ability to restore or enhance immune responses. Comparable data in studies investigating the effect of cefodizime on immune functions in immunocompromised patients such as elderly subjects, hemodialyzed or diabetic patients, BPCO subjects, patients undergoing surgical stress and patients with multiple myeloma are more important from a practical clinical point of view.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

[The procedures for using immunological study methods in different diseases].

The article deals with the basic principles of application of immunological methods for the diagnosis of the immune system disorders. A two-staged method of laboratory tests for the immune status evaluation was accompanied with a number of immunological methods which differed depending on the proper status of the immune system. The author stresses the clinical significance of the methods of the immune status evaluation and also gives the basic immunological criteria for the immunomodulatory therapy.

Autoimmune Diseases↗
PubMed1996

Exhaustion of CTL memory and recrudescence of viremia in lymphocytic choriomeningitis virus-infected MHC class II-deficient mice and B cell-deficient mice.

To study the contribution of CD4+ T cells and B cells to antiviral immunity and long term virus control, MHC class II-deficient and B cell-deficient mice were infected with lymphocytic choriomeningitis virus. In class II-deficient mice, which lack CD4+ T cells, the primary CTL response is virtually intact, and the infection is initially controlled in most organ sites including the blood. However, approximately 2 mo postinfection, CTL memory cannot be detected, and recrudescence of viremia to titers as high as seen during the acute phase of the infection is observed. To investigate whether this phenomenon could reflect participation of B cells and/or Abs in long term virus control, similar experiments were performed with mice that do not have mature B cells because of a disrupted membrane exon of the mu chain gene. In these mice, the cell-mediated immune response was slightly delayed, but transient virus control was observed in most mice. However, approximately 3 mo postinfection, blood virus titers were as high as observed during the acute infection, and no CTL memory could be demonstrated. These results indicate that Abs and/or B cells are required for permanent virus control and that in their absence, the virus-specific CTL potential becomes exhausted. Together our results indicate that while CD8+ cells play a dominant role in acute virus control, all three major components of the immune system are required for long term virus control.

Acute Disease↗
PubMed1995

Common problems in the diagnosis of immunodeficiency in children.

Primary immunodeficiency (ID) has an incidence of 1 in 10,000 and may have significant morbidity and mortality if not diagnosed and treated early. Children with signs and symptoms suggestive of immunodeficiency are often seen first by their paediatrician or family medical practitioner. For these reasons, it is essential that primary care physicians both of children and adults should be able to recognize the signs and symptoms of immunodeficiency and be knowledgeable about the screening procedures useful in the diagnosis of these diseases. However, this process is often complicated by the diverse presentations of immunodeficiency and the lack of specificity and relative inaccessibility of screening tests. The purpose of this paper is to address the major problems in diagnosis of immunodeficiency, including: 1) Which patients to seriously consider for diagnosis? 2) How to begin the work-up for primary immunodeficiency? 3) Which procedures are useful in the diagnosis of the various forms of immunodeficiency? and 4) What is the relative importance of immunoglobulin (IgG) subclasses?

Child↗
PubMed1996

The xid mutation diminishes memory B cell generation but does not affect somatic hypermutation and selection.

In this study, we examine the relationship between primary and secondary T cell-dependent immune responses using the response of xid mice to the hapten (4-hydroxy-3-nitrophenyl)acetyl (NP) as an experimental model. The reduced serologic primary immune response of xid mice was demonstrated to be caused by a substantially decreased Ab-forming cell (AFC) generation. Furthermore, the germinal center reaction in the primary xid immune response was diminished and the frequency of NP-specific memory B cells prior to secondary immunization was reduced 10-fold. Despite the poor primary response of xid mice, secondary exposure to Ag generated a response that was qualitatively and quantitatively equal to that of wt mice. The number of IgG1 AFCs in spleen and bone marrow increased equally in both groups, as did the proportion of AFCs secreting high affinity Ab in both locations. The extent and distribution of somatic mutations in the V(H) genes of xid secondary response B cells was also found to be normal, indicating that the xid gene product is not critical for the processes that result in affinity maturation. Thus, although xid mice generate memory B cells of normal phenotype but at a substantially lower frequency, this does not limit the magnitude of the secondary response. Therefore, our results imply that the reduced memory B cell frequency in xid mice is still above some threshold value necessary for a normal secondary immune response.

Animals↗