Increased proportion of B lymphocytes in human tonsils and appendices

Isolation of primary human B lymphocytes from tonsils compared to blood as alternative source for ex vivo application

B lymphocytes ('B cells') are components of the human immune system with obvious potential for medical and biotechnological applications. Here, we discuss the isolation of primary human B cells from both juvenile and adult tonsillar material using a two-step procedure based on gradient centrifugation followed by separation on a nylon wool column as alternative to the current gold standard, i.e., negative immunosorting from buffy coats by antibody-coated magnetic beads. We show that the nylon wool separation is a low-cost method well suited to the isolation of large amounts of primary B cells reaching purities ≥ 80%. More importantly, this method allows the preservation of all B cell subsets, while MACS sorting seems to be biased against a certain B cell subtype, namely the CD27⁺ B cells. Importantly, compared to blood, the excellent recovery yield during purification of tonsillar B cells provides high number of cells, hence increases the number of subsequent experiments feasible with identical cell material, consequently improving comparability of results. The cultivability of the isolated B cells was demonstrated using pokeweed mitogen (PWM) as a stimulatory substance. Our results showed for the first time that the proliferative response of tonsillar B cells to mitogens declines with the age of the donor. Furthermore, we observed that PWM treatment stimulates the proliferation of a dedicated subpopulation and induces some terminal differentiation with ASCs signatures. Taken together this indicates that the proposed isolation procedure preserves the proliferative capability as well as the differentiation capacity of the B cells.

A morphological and immunohistological study of the human and rabbit appendix for comparison with the avian bursa

Diversification of the primary antibody repertoire occurs in young rabbit appendix. As a prelude to molecular investigation of whether human appendix has a similar role, we compared the lymphoid morphology and distribution of common B- and T-cell subsets in frozen and/or paraffin-embedded normal appendix specimens at various ages. IgA, IgM and IgG staining patterns were similar in frozen human and rabbit appendices. The elongated follicles of the young human and rabbit appendices regressed with age to resemble Peyer's patches. Although similar in morphology to the bursa, human and rabbit appendix follicles differ in that they do not involute completely with age and contain significant numbers of germinal center (GC) T cells although the number is low early in life. If the human appendix functions as a primary lymphoid organ, it may occur during the first few months of age when the GC T-cell density is low.

Characteristic biochemical differences in human T and B lymphocytes separated on nylon wool

T and B lymphocytes from human tonsils were separated on a nylon wool column. T. cells are enriched in the nonadherent, B cells in the adherent fraction. Several enzymes and other markers were tested in separated and non separated lymphocyte populations. Certain enzymes and other properties can be used as T or B lymphocyte markers because of their preferential occurrence and because of the advantages of their estimation (simple, quick methods, objective evaluation). The following characteristics were considered as markers on the basis of our results: (I) acid phosphatase, Na+-K+-activated ATPase, BAEE-peptidase and chromium labeling in T lymphocytes; (II) 5'-nucleotidase, FITC-IgG binding, N-acetyl-D-glucosaminidase, thymidine and valine incorporation in B lymphocytes.

T cell subsets in the tonsil in relation to age analyzed with monoclonal antibodies (anti-leu antibodies) and fluorescence activated cell sorter (FACS)

The ratio of the cells reacting to anti-leu 1, 3a and 4 antibodies is as low as that of T cells in the tonsil to those in the peripheral blood. The number of the tonsillar cells reacting to anti-leu 2a and 7 antibodies is still smaller. Fluorescence intensity of tonsillar lymphocytes reacting to leu (1, 2a, 3a, and 4) antibodies is lower than that of peripheral blood lymphocytes. Adult tonsillar lymphocytes have higher ratios of the cells reacting to anti-leu 1, 2a, 3a, 4 and 7 antibodies than child tonsillar lymphocytes and fluorescence intensity of the cells reacting to these anti-leu antibodies tended to be higher in adult tonsillar lymphocytes. These findings suggest less cytotoxic/suppressor T and NK/K function cells in the tonsil than in the peripheral blood. From these, it is conceivable that the tonsillar lymphocyte constitution becomes closer to that of peripheral blood as the child grows up. Further, immature T cells are present in the tonsil, though in a small number. This tendency is stronger in children than in adults.

Subpopulation of adenoidal lymphocytes of recurrent infection in the upper respiratory tract

A subpopulation of adenoidal lymphocytes was determined by the E- and EAC-rosetting techniques in order to study an immunological profile of adenoids in 61 children with recurrent otitis media, rhinosinusitis or recurrent tonsillitis. Though there was no significant difference in E- and EAC-rosette forming cells of adenoid tissues from children with recurrent infection in the upper respiratory tract, our results indicated the following. (1) A higher proportion of EAC-rosette forming cells (EAC-RFC) without a change of E-RFC was found in the adenoids of children with recurrent tonsillitis than those without it. (2) The percentage of EAC-RFC appears to increase proportionally to the size of adenoid viewed on the X-ray film. (3) The higher percentage was more remarkable in cases with rhinosinusitis and recurrent otitis media. From the data obtained it is concluded that adenoids may play some part in immunity responses against infection in the upper respiratory tract reflecting adenoidal hypertrophy.

Characterization of clinical tonsil stages by their T-cell count. Immunopathological description of tonsils after a peritonsillar abscess

The T-cell counts in five different clinical tonsil stages are compared. No particularities were observed, with the exception of the condition after a peritonsillar abscess. The differences existing between the individual groups are discussed as age-dependent. A considerable increase in T-cells is found in the abscess tonsil compared with other tonsils and the T-cell count in blood. Its pathomechanism is discussed.

Percent distribution of T- and B-cells in tonsils of children, juveniles and adults

The percent distribution of T- and B-lymphocytes in tonsilar tissue of 122 patients from 2--68 years and both sexes was investigated. T-cells were determined by the E-rosetting technique and B-cells by immunofluorescence. We found 50.3% B-cells and 30.6% T-cells in tonsilar tissue. There was a significant decrease of IgM-receptor carrying cells with increasing age and with a converse behavior of the sum of IgA-, IgD-, IgE-receptor B-cells. In tonsils with acute inflammation and with hyperplasia IgM cells were also increased significantly when compared to cell counts in chronic tonsillitis. The results are discussed and compared to data from the literature.

Relative and absolute numbers of E- and EAC-rosette-forming cells in lymphoid organs

The percentage of lymphocytes of the blood and lymphoid organs of young pigs were determined by forming rosettes with pretreated sheep red blood cells (AET-rosettes) or with sheep red blood cells coated with antibody and complement (EAC-rosettes). The mean figures for AET-rosettes were 70% for the blood, 93% for the thymus, 78% for lymph-nodes and 68% for the spleen. For EAC-rosettes the numbers were 16%, 0%, 16% and 19% respectively. The absolute numbers of rosette-forming lymphocytes were estimated on the basis of previously determined numbers of lymphoid cells in young pigs. Even by excluding the data for the thymus, there would be about three times more AET-rosette forming lymphocytes than EAC-rosette forming cells in the whole animal. About 11% of all lymphocytes did not show any of these markers. Data on the numbers of "B" and "T" lymphocytes in human lymphoid organs from the literature were summarized and compared to those found in pigs and thus, the absolute numbers for a young adult man estimated.

Distribution of B, T, and O lymphocytes in blood and tissues of normal humans reflecting a kinetic model

The occurrence of the lymphocyte subpopulations TE, BFc, BC3, BFc + C3, BIg, and O-, percentage as well as absolute, was studied in lymphocyte suspensions from tonsils, abdominal lymph nodes, spleens, bone-marrow aspirates, and at the same time in venous blood. The absolute lymphocyte content (number of lymphocytes per g tissue) was highest in the abdominal lymph nodes, lower in the spleens and tonsils, and lowest in the blood. TE lymphocytes were found in the significantly highest percentage, 60%, in the blood. B lymphocytes, comprising BFc + C3 plus BIg, were present in the highest percentage in the bone marrow: 74%. Tonsils, spleens, and abdominal lymph nodes contained fewer B lymphocytes, and the blood fewest: 39%. A significant correlation was found only between the absolute numbers of T and B lymphocytes. A relationship between the absolute number of T lymphocytes and the total number of B lymphocytes as well as fractions thereof was thus demonstrated in the various tissues and in the blood and also between the blood and the tissue. O- lymphocytes were found in bone marrow, lymph nodes, and spleens, apparently as markerless precursors of other subpopulations. The main conclusion of the study is: In the lymphocytokinetic system the T lymphocytes must play a guiding role as an afferent vector, trigging the B fractions which thus constitute the efferent vector of the system.