T and B Lymphocytes: Striking Differences in Surface Membranes

Mehrishi, J.N.; Zeiller, K.

doi:10.1136/bmj.1.5904.360

Cited by 43 publications

(17 citation statements)

References 13 publications

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“…In our calculations, the representative surface area of FDC in the whole human body is a few thousand cm 2 , corresponding to ϳ10 9 FDC with a surface area of a few hundred m 2 per cell (24,27). Parameter values.…”

Section: Methodsmentioning

confidence: 99%

Contribution of Follicular Dendritic Cells to Persistent HIV Viremia

Perelson

2013

J Virol

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HIV-1 infections cannot be completely eradicated by drug therapy, as the virus persists in reservoirs. Low-level plasma viremia has been detected in patients treated for over 7 years, but the cellular compartments that support this low-level viremia have not been identified. The decay of HIV-1 during treatment appears to occur in four phases, with the 3rd and 4th phases occurring when the virus is below the limit of detection of conventional assays. Here, we focus on the 3rd phase of decay, which has been estimated to have a half-life of 39 months. We show that follicular dendritic cells (FDC), which have been identified as an HIV reservoir, can be the main source of the low-level viremia detected during the 3rd phase of decay and contribute to viremia at even longer times. Our calculations show that the kinetics of leakage of virus from FDC is consistent with three types of available clinical data. Highly active antiretroviral therapy (HAART) is effective in suppressing progression of HIV infection. In the first few months of suppressive therapy, the plasma HIV-1 RNA load experiences a biphasic decay (1-5). The first phase has a short halflife (1 to 2 days) and is attributed to the loss of infected activated CD4 ϩ T cells. The second phase has a half-life of 1 to 4 weeks and has been attributed to the loss of long-lived infected cells such as resting CD4 ϩ T cells or macrophages (4, 6). The presence of other decay phases has been suggested (5, 7), and a recent study by Palmer et al. (8), using a very sensitive assay with a lower limit of quantification of 0.63 HIV RNA copies/ml (9), identified a third and fourth decay phase in patients on suppressive therapy for 7 years (Fig. 1). Phase 3 had a half-life, 3 , of 39 weeks (supported by a recent study [10]), and phase 4 showed a nearly constant plasma viral load for the period studied out to 7 years. Overall, the median plasma viral load, V(t), for patients on suppressive therapy can be represented by the following equation:where t is the time on therapy, V 1 (t) through V 4 (t) designate the contributions to the plasma viral load of the virus generated by the compartments 1 through 4, V 1 (0) through V 4 (0) designate the contributions of the virus generated by compartments 1 through 4 to the baseline viral load, i ϭ

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Section: Methodsmentioning

confidence: 99%

Contribution of Follicular Dendritic Cells to Persistent HIV Viremia

Perelson

2013

J Virol

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“…It would follow that the T cells used in the study of Mehrishi and Zeiller (1974) were very likely to be a limited subgroup of cells rich in surface sialic acid. Meanwhile, it has been described that Fc11 • R is indeed readily demonstrable with T lymphocytes but can also be detectable on B lymphocytes as well if carefully examined (Pichlar and Broder 1978;Kataoka et al 1982).…”

Section: Discussionmentioning

confidence: 99%

“…Assays by the method revealed the presence of 2.46 u g surface sialic acid per 1 X 10' human peripheral blood lymphocytes. According to Mehrishi and Zeiller (1974), the amounts of surface sialic acid of T and B lymphocytes separated by continuous electrophoresis without carrier were determined to be 21 and 11 p g per mg of protein respectively. The finding seems to be quite reasonable since the separation of these subclasses of lymphocytes by electrophoresis is based on the difference in surface electric charge which is determined by the amount of sialic acid present on the lymphocyte membrane.…”

Section: Discussionmentioning

confidence: 99%

Expression of receptors for Fc portion of IgM (Fc.MU.R) and surface neuraminic acid on the human peripheral lymphocytes.

Kikuchi

Toyota

1985

Tohoku J. Exp. Med.

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The purpose of this investigation is to establish a method of quantitation of sialic acid on the lymphocyte membrane surface and to clarify the importance of sialic acid in the functional manifestation of the lymphocyte receptor for the Fc portion of IgM (Fcp •R) as well as the cell surface. The experiments yielded results leading to the following conclusions : (1) Cell surface sialic acid can be exclusively recovered at consistent rates by treatment of lymphocytes with 0.1 ITJ of neuraminidase in the presence of Ca++ at 37°C for 30 min. (2) The sialic acid obtained, though in minute quantities, was accurately quantitated by the TBA method. (3) By these procedures, the amount of sialic acid present on the cell membrane of human peripheral blood lymphocytes was determined to be 2.46,ug/10'. (4) Surface sialic acid on lymphocytes cultured at 37°C after treatment with neuraminidase was resynthesized sufficiently at about 6 hr. (5) On the cell membrane of lymphocytes deprived of Fc,u • R by treatment with neuraminidase, the receptor for IgM Fc became redetectable following incubation of the cells at 3TC ; the timecourse of redevelopment of Fcp • R showed a striking coincidence with that of sialic acid resynthesis. (6) A sufficient redevelopment of Fc,u • R occurred in 6 hr of incubation of neuraminidase-treated Fcp • R-deprived lymphocytes ; the time required for sufficient redevelopment was comparable to that reported for pronasetreated lymphocytes. It is concluded from these findings that Fc,u • R deprived of sialic acid is no longer repaired while the receptor is resynthesized de novo on incubation of lymphocytes under adequate conditions. Fc,u-receptor ; sialic acid Studies have made a rapid progress in these several years in the understanding of the function and properties of the receptor sites specific for the Fc portion of the immunoglobulin molecule (Fc•R) present on the surface membrane of various subclasses of lymphocytes. The receptor for the Fc fragment of IgG (Fcy•R), for example, is estimated to consist of a single peptide chain with a

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“…Enzymatic Digestion.-Aliquots of the washed lymphocyte suspensions of a single patient (case 11) were treated with Vibrio cholerae neuraminidase (Mehrishi and Zeiller, 1974 (Collins et al, 1974;Smith and Haegert, 1974) these lymphoblasts with neuraminidase (Chapel, 1973;Mehrishi and Zeiller, 1974) did not increase the number of cells with markers and failed to show masked determinants.…”

Section: A) For Scanning Purposesmentioning

confidence: 99%

Acute lymphoblastic leukaemia: a heterogenous disease.

Haegert¹,

Stuart²,

Smith³

1975

BMJ

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In marginal cases the presence of a thymoma, age over 50 years, bulbar involvement, and a thoracotomy or sternum-splitting incision are other factors favouring the need for tracheostomy and artificial ventilation. In this series patients who had artificial ventilation required it for more than 12 days (with the exception of one patient given tubocurarine), and we believe that if artificial ventilation is predicted as being necessary then tracheostomy, if not already done, should be performed at the time of thymectomy to spare the patient days of discomfort with an endotracheal tube.We suggest that there are two safe policies for the management of the patient with myasthenia gravis subjected to thymectomy. The first is routine tracheostomy and artificial ventilation, which allows withdrawal of anticholinesterases in safety and avoids the problem of manipulation of drugs in the immediate postoperative period. In our opinion, however, this policy entails needless tracheostomy and ventilation in many patients. The second safe policy described here is to continue the preoperative drug regimen in the postoperative period and select patients preoperatively for tracheostomy and artificial ventilation principally on the preoperative vital capacity. Compromise within these two policies is likely to lead to emergency intubation and tracheostomy in unfavourable circumstances.We wish to acknowledge the skill and attention of our surgical colleagues the late Mr. L. Pile, Mr. A. J. Gunning, and especially Mr. C. Grimshaw, who performed most of the thymectomies and introduced the new surgical approadh mentioned in the text. We also thank the staff of the respiration unit at Churchill Hospital who helped with the care of these patients.Requests for reprinits should be addressed to:

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T and B Lymphocytes: Striking Differences in Surface Membranes

Cited by 43 publications

References 13 publications

Contribution of Follicular Dendritic Cells to Persistent HIV Viremia

Contribution of Follicular Dendritic Cells to Persistent HIV Viremia

Expression of receptors for Fc portion of IgM (Fc.MU.R) and surface neuraminic acid on the human peripheral lymphocytes.

Acute lymphoblastic leukaemia: a heterogenous disease.

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