Changes In Surface Antigens Research Articles

Functional properties of Ly 11.2 lymphocytes: a role for these cells in leukemia?

Functional studies of lymphocyte subpopulations reveal that Ly 11.2, a newly defined T cell surface antigen, is present on prothymocytes and natural killer cells, but not on suppressor T cells for antigen-specific IgE antibody responses, Ly 1+, 2-, 3- helper T cells nor on tumor-specific cytotoxic effector cells. Changes in the expression of Ly 11.2 regularly accompany leukemogenesis and are quite distinct from changes of other cell surface antigens thus far observed. After intrathymic inoculation of radiation leukemia virus (RadLV), many more Ly 11.2-positive cells are found expressing viral antigens than cells expressing other cell surface phenotypes. In addition, after RadLV inoculation, significantly more Ly 11.2-positive cells can be found in the thymus of susceptible mice than in the thymus of resistant mice. The greater availability of permissive (Ly 11.2-positive) cells in susceptible vs resistant hosts at the time when infectious virus is present may account for the shorter latency period and high leukemia incidence of susceptible vs resistant mice.

The role of the World Health Organization in the study of influenza.

The World Health Organization (W.H.O.), since its inception in 1947, has given close attention to influenza. In its early years W.H.O. laid the foundations of its present network of over 100 national influenza centres and collaborating laboratories which today constitute the backbone of its influenza activities. The activities of the network include the isolation and characterization of influenza strains and the early notification of any changes in surface antigens, the preparation of reference reagents, standardization of diagnostic procedures, formulation of requirements for vaccines, training, and collaboration in research. The efficacy of the network has been proved in the 1957, 1968 and 1977 epidemics. Collaborative research organized by W.H.O. has made important contributions to our understanding of the epidemiology of influenza, including the possible role of lower animals as the origin of some pandemic strains. The latter subject is briefly discussed.

Age dependent reaction of mouse thymus cells with autologous and syngeneic erythrocytes

The age dependent events influencing the rosette forming capacity of Balb/c thymus and spleen cells against autologous or syngeneic erythrocytes were examined. A large number of autologous and syngeneic rosette forming cells (RFC) were observed in normal Balb/c mice in vitro. RFC were significantly greater in the thymus than in the spleen. The rosette forming T-cells (T-RFC) have the following characteristics: newborn Balb/c thymus has T-cells which react with syngeneic erythrocytes from older donors. The T-RFC showed broad cross-reactivity with erythocytes from other mouse strains but low reactivity with human or sheep erythrocytes. The auto and syngeneic T-RFC could be enhanced by non-specific serum proteins (FCS or BSA) or EDTA but was effectively inhibited by normal mouse serum. T-RFC resided in the cortisone sensitive population. The data indicate that the development of autologous and syngeneic rosette formation of thymus cells is dependent on the age of the erythrocyte donor. The age dependent change on the erythrocyte surface occurred relatively early in the life of the animal. The results also imply that certain subpopulations of thymus lymphocytes are capable of recognizing possible surface antigenic changes of the erythrocytes.

Surface Antigen Changes Accompanying Lymphocyte Activation

It is here shown that some noncongenic anti-H-2 antisera produced by using normal spleen cells at the immunogen can contain cytotoxic antibody activity against activated, but not resting, lymphocytes of unrelated H-2 haplotype strains. Reactivity was noted against lymphocytes activated in vitro with T- or B-cell mitogens, or in vivo by antigenic stimulation. Analysis of the results indicated that the anti-activated lymphocyte activity was most likely related to production of anti-Ala-1 ('activated lymphocyte antigen') alloantibodies. This appears to occur as a result of donor lymphocyte activation during production of the anti-H-2 antisera, using Ala-1-incompatible donor and recipient combinations, where the donor cells are competent to recognize and react against host H-2 incompatibilities. These results confirm the finding that lymphocyte activation can be accompanied by the expression of an antigen that is either absent or weakly expressed on resting lymphocytes.

Surface immunoglobulins, a possible mechanism for the persistence of Trypanosoma lewisi in the circulation of rats.

The results presented below show that the dividing and adult forms of T. lewisi share common antigens and indicate that the persistence of adult forms in the circulation of rats immune to reinfection is not due to a change in surface antigens as has been postulated. Using a rabbit anti-rat immunoglobulin serum, the presence of rat immunoglobulins on the surface of adult trypanosomes could be demonstrated. These immunoglobulins were not complement-fixing or opsonic. It is suggested that these immunoglobulins are responsible for the persistence of the adult forms in the circulation of the rat.

Membrane antigenic changes associated with PHA transformation of mouse spleen cells in vitro.

The changes in lymphocyte surface antigens associated with blast transformation have been studied by membrane immunofluorescence. When mouse spleen cells were stimulated in vitro with phytohaemagglutinin for 4 days virtually all of the resulting blast cells were shown to have histocompatibility (H-2d), theta(θ)and mouse-specific T lymphocyte (MTLA) antigens; approximately 50% had detectable surface immunoglobulin and 70% mouse-specific B lymphocyte antigen (MBLA). The intensity of the staining reactions on blast cells was increased for the anti-MTLA serum and reduced for the anti-immunoglobulin and anti-MBLA sera when compared with the staining of fresh spleen cells. No difference was detected for the anti-θ and anti-H-2d sera. Cap formation was detected on fresh spleen cells labelled with any of the antisera, but after stimulation only anti-immunoglobulin-treated blasts showed the cap pattern.The simultaneous expression of B-and T-cell markers on PHA transformed cells suggests a convergence of the lympho...

Cell surface antigenic changes induced in normal adult rat liver cells by carcinogen treatment in vitro.

Normal rat liver cell lines treated with the chemical carcinogen N-methyl-N-nitrosourea (MNU) elicited antibody production (detected by membrane immunofluorescence test in vitro) when injected into a highly inbred strain of rats from which the liver cells were originally isolated. In contrast, the control cells which were untreated did not evoke humoral antibodies. Antisera raised against the MNU-treated cells reacted not only with the immunizing cells, but also with 3'-methyl-4-dimethyl aminoazobenzene and 3-methylcholanthrene-treated cells. However, this antiserum failed to react with cells treated with either aflatoxin or N-acetoxy-2-acetyl-aminofluorene. Embryonic antigens were found to be absent from the normal adult liver cell line. Preliminary results indicated that none could be detected on carcinogen-treated cells either.

Changes in surface antigens of SV40-virus transformed cells.

Changes in surface antigens of SV40-virus transformed cells.

Surface Antigenic Changes in Bacillus cereus during Germination and Sporulation as Shown by Fluorescent Staining

Antigenic changes occurring on the surface of Bacillus cereus during sporulation and germination have been followed, using fluorescent labelled antibodies.

Surface Antigenic Changes in Bacillus cereus during Germination and Sporulation as Shown by Fluorescent Staining

Surface Antigenic Changes in Bacillus cereus during Germination and Sporulation as Shown by Fluorescent Staining

SMALL-CELL SEGREGANTS FROM A POSSIBLY HOMOZYGOUS DIPLOID STRAIN OF ESCHERICHIA COLI.

Ogg, James E. (Colorado State University, Fort Collins) and Ronald D. Humphrey. Small-cell segregants from a possibly homozygous diploid strain of Escherichia coli. J. Bacteriol. 85:801-807. 1963.-Evidence was presented to show that a homozygous possibly diploid strain of Escherichia coli, when grown in a chemically defined medium under the conditions described in this report, will yield small-cell segregants that have haploid characteristics. The segregants have one-half as much deoxyribonucleic acid per cell as the diploid, give exponential survival curves when exposed to X rays, and have fermentative characteristics similar to the original haploid parent strain of the homozygous diploid strain. No detectable changes in surface antigens were associated with the segregation phenomenon. The haploidlike segregants can be converted to the diploid radiation-resistant state by growing them in the presence of camphor vapors.