NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/sci/med/aids/2188

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From: Billi Goldberg <[e-mail]>
Subject: Clonal Expansion & Lymphocyte Transfer
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Note: Copyright 1992, Dan R. Greening. Non-commercial reproduction allowed.
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    CD8 CLONAL EXPANSION AND LYMPHOCYTE TRANSFER TREATMENTS
                         Billi Goldberg

Some of the latest treatments for AIDS includes autologous CD8 clonal
expansion and allogeneic lymphocyte transfer. It is my understanding
that the cells will by expanded by using PHA (phytohemagglutinin) and
activated by IL-2. According to Romagnani, there are subsets of CD8
cells which produce IL-4, IL-5, and IL-10; these cytokines have been
shown to downregulate TH1 responses. In Taguchi's study, it is shown
that IL-5 produced by Th2 cells enhances IgA synthesis. It is possible
that some of the cytokines produced by CD8+ subsets of the Th2 type
could initiate IgG synthesis. There is also the question of whether or
not IFN-gamma is required to initiate effective cytotoxic responses from
CD8+ CTLs. It appears that IFN-gamma is required in vitro and in vivo to
activate CTLs.

Research has shown not only CD4+ cytotoxic subsets but CD8+ helper
subsets albeit a minimal number just to completely confuse the issue.

Busch's study clearly delineates the problems associated with allogeneic
transfer of lymphocytes.

The question now becomes how effective the CD8 clonal expansion and
lymphocyte transfer treatments will be considering the research of
Romagnani, Sher, Shearer, Taguchi, Mossman and others.
=======================================================================
Romagnani S. Human TH1 and TH2 Subsets: Regulation of Differentiation
and Role in Protection and Immunopathology. International Archives of
Immunology December 1992;98:279-285.

Abstract: A large body of evidence has accumulated suggesting the
existence of human TH1 and TH2 subsets, reminiscent of those described
for mouse T cells. Human TH1 cells develop in response to intracellular
bacteria and viruses, do not provide help for IgE synthesis and are
cytolytic. Human TH2 cells develop in response to allergens and helminth
components, provide help for IgM, IgG, IgA, and IgE synthesis and lack
cytolytic potential. The cytokine profile of 'natural' immunity (high
IFN-gamma and no IL-4 production) evoked by intracellular bacteria and
viruses that activate both macrophage and NK cells, probably determines
the phenotype of the subsequent specific TH1 response. Absence or low
concentration of IFN-gamma and early production of IL-4 by non-T cells
or by T cells themselves, that occur in response to allergens and
helminth components, probably favor the development of TH2 cells. TH1
and TH2 cells play different roles not only in protection against
exogenous offending agents, but also in immunopathology. TH1 cells are
involved in contract dermatitis, organ-specific autoimmunity and
allograft rejection. TH2 cells are responsible for the initiation of the
allergic cascade.

Page 280:

DO CD8+ TH1 AND TH2 CELLS EXIST?

The demonstration that human CD4+ T cells can be subdivided into
different subsets based on their profile of cytokine production raises
the question of whether such heterogeneity exists among CD8+ T cells as
well. In the mouse, CD8+ T cells mainly produce the TH1-cell cytokine
pattern. However, high proportions of IL-5 producing CD8+ clones have
been derived from the murine gut mucosa. Accordingly, the great majority
of human CD8+ T-cell clones derived from the plasma blasts (PB) of
normal individuals also exhibit a TH1-like profile. However, two subsets
of CD8+ clones specific for M. Leprae antigens have been described.
CD8+ cytotoxic clones produced IFN-gamma and IL-10, but not IL-4 (type
1), whereas CD8+ suppressor clones produced substantial amounts of
IL-4 (type 2). More recently, high proportions of CD8+ T-cell clones
producing both IFN-gamma and IL-5 but not IL-4 were derived from
bronchial biopsy specimens of patients with toluene diisocyanate
(TDI)-induced asthma following inhalation of TDI. Finally, CD8+
clones with a clearcut TH2 phenotype (producing IL-4 and IL-5, but
not IFN-gamma) were derived from the Kaposi's sarcoma skin lesions o
f patients with AIDS. All thes finding encourage the view that distinct
CD8+ T-cell subset can be discriminated by analysis of their lymphokine
profiles.
=======================================================================
Busch MP; Lee TH; Heitman J.
Allogeneic leukocytes but not therapeutic blood elements induce
reactivation and dissemination of latent human immunodeficiency virus
type 1 infection: implications for transfusion support of infected
patients. Blood, 1992 Oct 15, 80(8):2128-35.

Abstract: Various immunologic stimuli and heterologous viral regulatory
elements have been shown to increase susceptibility to, and replication
of, human immunodeficiency virus type 1 (HIV-1) in lymphocytes and
monocytes in vitro. Transfusion of allogeneic blood components from
heterologous donors constitutes a profound immunologic stimulus to the
recipient, in addition to being a potential route of transmission of
lymphotropic viral infections. To investigate the hypothesis that
transfusions, and particularly those containing leukocytes, activate
HIV-1 replication in infected recipient cells, we cocultured peripheral
blood mononuclear cells (PBMC) from three anti-HIV-1-positive
individuals with allogeneic donor PBMC, as well as partially purified
populations of donor lymphocytes, monocytes, granulocytes, platelets,
and red blood cells (RBC) and allogeneic cell-free plasma. Allogeneic
PBMC induced a dose-related activation of HIV-1 expression in in vivo
infected cells, followed by dissemination of HIV-1 to previously
uninfected patient cells. Activation of HIV-1 replication was observed
with donor lymphocytes, monocytes, and granulocytes, whereas no effect
was seen with leukocyte-depleted RBC, platelets, or plasma (ie,
therapeutic blood constituents). Allogeneic donor PBMC were also shown
to upregulate HIV-1 expression in a "latently" infected cell line, and
to increase susceptibility of heterologous donor PBMC to acute HIV-1
infection. Studies should be performed to evaluate whether transfusions
of leukocyte-containing blood components accelerate HIV-1 dissemination
and disease progression in vivo. If so, HIV-1-infected patients should
be transfused as infrequently as possible and leukocyte-depleted
(filtered) blood components should be used to avoid this complication.
=======================================================================
Fong TA; Mosmann TR. Alloreactive murine CD8+ T cell clones secrete the
Th1 pattern of cytokines. Journal of Immunology, 1990 Mar 1,
144(5):1744-52.

Abstract: A large panel of CD8+ mouse T cell clones expressed the
cytokine synthesis pattern characteristic of Th1 clones. CD8+ clones
synthesized IFN-gamma and lymphotoxin at levels similar to Th1 clones,
whereas IL-2 was synthesized by only 50% of the clones and at
significantly lower levels compared to Th1 clones. CD8+ clones also
produced substantial amounts of granulocyte/macrophage-CSF, TY5, P500,
and TNF-alpha which are expressed preferentially by Th1 clones and at
lower levels by Th2 clones. The level of IL-3 produced by CD8+ clones
was approximately 10% of that produced by Th1 and Th2 clones. Some CD8+
clones expressed low levels of the Th2-preferential product
preproenkelphalin. None of the CD8+ clones expressed detectable levels
of the Th2-specific products IL-4, IL-5, and P600, and the great
majority did not express IL-6. The cytokine profile of CD8+ clones is
representative of that secreted by activated normal CD8+ splenocytes,
which includes IFN-gamma, low levels of IL-2 and IL-3 but no IL-4 or
IL-5. Inasmuch as many Th1/Th2 functions are cytokine mediated, the
striking similarity of the Th1 and CD8+ cytokine secretion patterns
helps to explain why these two cell types share certain functions such
as DTH, and also suggests that further common functions may be
discovered in the future.
=======================================================================
Taguchi T; McGhee JR; Coffman RL; Beagley KW; Eldridge JH; Takatsu K;
Kiyono H. Analysis of Th1 and Th2 cells in murine gut-associated
tissues. Frequencies of CD4+ and CD8+ T cells that secrete IFN-gamma and
IL-5. Journal of Immunology, 1990 Jul 1, 145(1):68-77.

Abstract: After Ag and/or mitogen stimulation, cloned mouse Th1 and Th2
cells produce different cytokines that contribute to induction of
particular B cell isotype responses. In this regard, IL-5 produced by
Th2 cells has been shown to enhance IgA synthesis in LPS-triggered
splenic (SP) B cell or in unstimulated Peyer's patch (PP) B cell
cultures. This raises the possibility that Th2 cells may occur in higher
frequency in gut-associated tissues, because B cells in these areas are
committed to IgA synthesis. We have used an ELISPOT assay to detect
individual T cells producing IFN-gamma or IL-5. For the IL-5 assay, the
mAb TRFK-5 and biotinylated TRFK-4 were used in coating and detection,
respectively, whereas the mAb R4-6A2 and biotinylated XMG 1.2 were
similarly used for enumeration of IFN-gamma-specific spot forming cells
(SFC). Specificity of each assay was tested by using Con A-activated,
cloned Th1 (H66-61) or Th2 (CDC-25) cells, where the Th1 cells only
produced IFN-gamma SFC and the Th2 cells only gave IL-5-specific spots.
Further, preincubation of biotinylated TRFK-4 or XMG 1.2 with rIL-5 or
IFN-gamma, respectively, abrogated the formation of specific spots when
tested with Con A-activated SP CD4+ T cells. Both IFN-gamma and IL-5
were produced de novo, because treatment of T cells with cycloheximide
inhibited both IFN-gamma and IL-5 SFC. We have assessed the numbers of T
cells spontaneously secreting these cytokines in PP and in lamina
propria and intraepithelial lymphocyte (LPL and IEL) populations.
Moderate levels of IL-5 SFC occurred in the IEL subset, whereas higher
levels existed in the LPL population. Although significant numbers of
IFN-gamma SFC (Th1-type) were also seen in LPLs, the frequency of IL-5
SFC was always higher (Th1:Th2 in LPL = 1:3). In IELs, equal numbers of
IFN-gamma and IL-5 SFC were seen. Interestingly, CD8+ IEL T cells
produced these two cytokines. In contrast, T cells freshly isolated from
PP, an IgA inductive site, contained smaller numbers of IL-5- or IFN-
gamma-secreting cells and SP T cells had essentially no SFC. When PP or
SP T cells were stimulated with Con A, significant and approximately
equal numbers of IFN-gamma- and IL-5-producing cells appeared.(ABSTRACT
TRUNCATED AT 250 WORDS)