Blastogenic response of human lymphocytes to early antigen(s) of human cytomegalovirus

Clinical significance of CMV-specific T helper responses in lung transplant recipients

BACKGROUND

Cytomegalovirus (CMV) disease continues to be a major problem for lung transplant patients who generate an inefficient immune response to control this viral infection. Both T helper and cytotoxic T cells are thought to play an important role in prevention and control of CMV disease. We investigated the clinical significance of CMV-specific memory responses in lung transplant recipients.

METHOD

Peripheral blood samples (140) were collected from 99 lung transplant recipients. Patients were grouped according to their pre-transplant CMV serological status as recipient/donor (R-/D+, 25 patients), 28 R+/D+ patients, 35 R+/D- patients and 11 R-/D- patients. Memory responses to CMV whole antigen, 5 CMV proteins, and tetanus toxoid (TT) were measured in a 6-day proliferative assay. Results were expressed as the stimulation index (SI = experimental cpm/background cpm), and were considered positive if the SI was >3 and the cpm values were over 1,000.

RESULTS

The frequency of positive CMV memory responses was similar in three groups: 64% for R-/D+, 63% for R+/D+ and 56% for R+/D- except for R-/D- (21%). The memory response to TT was similar for all four groups (70% of samples were positive). The level of responsiveness to individual CMV proteins was much higher in R+/D+ group (65%) than the other two groups (35% for R+/D-, and 31% for R-/D+). We determined the temporal relationship between the presence of CMV-specific memory responses and the diagnosis of CMV disease. In the R-/D+ group, 16 of 17 patients who had CMV disease eventually developed CMV-specific memory. In those patients (n = 3) who failed to develop CMV-specific T helper response for a prolonged time, all had recurrent CMV disease. In the R+/D+ group, 4 of 8 patients with CMV disease exhibited CMV-specific memory responses. Three of 4 patients in whom we observed a persistent absence of CMV-specific memory had multiple episodes of CMV pneumonitis. In the R+/D- group, only one of 4 patients with CMV disease had suppressed CMV-specific memory response after first episode of CMV pneumonitis and had recurrent disease.

CONCLUSION

In lung transplant recipients, the loss or persistent lack of CMV-specific memory following infection was associated with chronic CMV disease. These data suggest that monitoring T helper memory responses following primary CMV infection or after augmented immunosuppression for treatment of rejection may identify those patients at risk for morbidity associated with recurrent CMV disease.

The cellular immune response to cell-associated and cell-free cytomegalovirus (CMV) antigens after primary CMV-infection in non-immunocompromised hosts: development and maintenance of CMV-latency and its influence on immunocompetence

Development and maintenance of cellular immunity to cell-associated CMV-antigens (CMVFF) was investigated in non-immunocompromised hosts during the first year (group I, n = 11) and 1 to 5 years (group II, n = 9) after a symptomatic primary CMV infection, as well as in healthy CMV-seropositive controls without a history of CMV disease (group III, n = 28). During the acute phase (0-2 months) of a primary CMV-infection CMVFF-induced lymphocyte proliferation was severely decreased compared to that in the post-illness phase (5-12 months), and to that in groups II and III. After the reconvalescent period (3-4 months) it gradually increased to levels seen in group III. In group II higher responses to CMVFF were found than in group III or during the post-illness phase of a primary infection. In general CMV-virion induced lymphocyte proliferation showed the same pattern of development as the CMVFF-induced lymphocyte response, but during the acute phase (0-2 months) a lack of correlation was observed between lymphocyte proliferation to CMVFF and CMV-virions. Lymphocyte proliferation to PHA, Con A, allogeneic lymphocytes and recall antigens were severely depressed in the acute phase of a primary CMV-infection and restored gradually to levels seen in groups II and III, with the exception of Con A-reactivity. The latter response remained depressed when compared to healthy seropositive controls, not only during the post-illness period, but also later on (group II).

Isolation of tumor disturbing factor on the proliferation of tumor cells in human serum

The classified sediment with ethanol from sera of nude mice and humans showed a disturbing effect on L1210 cells in vitro and a lifesaving effect on L1210 cell-bearing mice in vivo. This factor was purified more than 2300-fold to a specific activity of approximately 1 X 10(5) U/mg by ethanol classified precipitation, Sephadex G-200 gel filtration, DEAE cellulose ion exchange chromatography with Nacl and pH gradient aqueous solution, and preparative polyacrylamide gel electrophoresis.