Role Of K(v) Channel Of Lymphocyte In Immune Response And Adaptation To Hypoxia

Presently, the study of hypoxia and its adaptation mechanism is mainly focus on the oxygen intake related system, include respiratory, circulatory and central nerve system which was highly sensitive to the concentrition of oxygen. Till now the study of immunity alteration of the body after it exposure to hypoxia is few, and it was investigated only at the whole body level, however the mechanisms of immune system adaptation to hypoxia were not involved.Lymphocyte plays a key role in the body immune processes as it secretes some cytokines, such as IL-2, which mediate immune cell activations and proliferation. The K(v) channel in lymphocyte exert an important action in controlling membrane potential, regulating cell volume and facilitating the process of cell activation and proliferation through controlling the outflow of potassium ion. This study will observe the effect of hypoxia on immune function at cell level and revealing the relationship between the expression of K(v) channel and immune function of lymphocyte by using patch-clamp and biomolecular technique, so as to analyze the role of K(v) channel in hypoxia adaptation.I . Recording and analysis the properties of K(v) channel in human peripheral lymphocyteThis study was carried out on human peripheral lymphocyte by using whole cell patch-clamp technique. It demonstrated that in 45 cells, the amplitude of K~+-current was 238.2 ± 70.3 pA, the actionpotential was -37.6+2.7mV, there was no inactivation phenomenon (use dependent ) under 40mV\ 200ms depolarization. The time of channel closing constant was 112.6 + 10.2ms under -60mV repolarization, and the channel cloud be blocked by lOmM TEA. II. Role of K(v) channel in the processes of lymphocyte activation and proliferationTo invetigate the role of K(V) channel in process of lymphocyte activation and proliferation, patch-clamp technique , radioimmuno-assay and fluroscein assay had been used to measure the current of K(V) channel, [Ca2"1"];, the amount of IL-2 secretion and the proliferation degree of lymphocyte under resting , proliferating and TEA blocked proliferating condition. The results suggested that all the parameters increased markedly and with statistic significant in the PHA group; but compared with PHA group, all the parameters in PHA +TEA group were decreased. The relative analysis showed that the [Ca2+]j was highly related to the amplitude of current of K(v) channel. It suggested that K(v) channel play a key role in the process of lymphocyte activation and proliferation. IE. Role of K(v) channel of lymphocyte in immune response andadaptation to hypoxia.By using patch-clamp, ELISA and RT-PCR technique, the expression and current of K(V) channel and body immunity were measured in acute and hypoxia adaptation. 1.Alterations of expression and current of K(v) channel and bodyimmunity in acute hypoxia.Compared with control group, the expression and current of K(v) channel, amount of IL-2 secretion and the degree of lymphocyte proliferation all declined, but IgG secretion did not chang significantly. It suggested that hypoxia had no harm to B cell function and body fluid immunity, meanwhile the decline of cellular immunity during acute hypoxia might related to the decrease of expression of K(v) channel. 2.Alteration of the expression and current of K(v) channel and bodyimmunity in hypoxia adaptationCompared with acute hypoxia group, except the amount of IgG secretion, the other parameters elevated significantly. It suggested that the immune function could be improved through hypoxia adaptation. Acting as a hypoxia sensitive gene, the K(v) channel may play an important role in hypoxia adaptation. 3.Alteration of the expression and current of K(v) channel and bodyimmunity under TEA+ hypoxia adaptationIn this group, the expression and current of K(v) channel, amount of IL-2 secretion and the degree of lymphocyte proliferation all declined markedly compared with hypoxia adaptation group, especially for the current of K(v), but there was no significant change for IgG secretion. It suggested further that the K(v) channels mediated the immune regulating effect in hypoxia adaptation by boost the current of K(v) channel through increased the expression of it.In conclusion: l.In 45 cells , the amplitude of K+-current was238.2 + 70.3 pA, the action potential was -37.6+2.7mV, there was no inactivation phenomenon (use dependent ) under 40rnV\ 200ms depolarization, the time of channel closing constant was 112.6 + 10.2ms under -60mV repolarization, and the channel cloud be blocked by lOmM TEA; 2.K(v) channel play an important role in the processes of lymphocyte activation and proliferation; 3.In acute hypoxia, B cell and body fluid immunity were not injured , however the immune function of T cell declined, it may related to the decrease of the expression of K(v) channel; 4.The gene in lymphocyte that express K(v) channel might be a hypoxia sensitive one, it expressed more in hypoxia adaptation to facilitate the processes of lymphocyteactivation and exert its immune adaptation effect.