By
From the * Department of Immunology, Keio University School of Medicine, Shinjuku-ku, Tokyo
160-8582, Japan; the Laboratory of Immunology, Central Institute for Experimental Animals,
Kawasaki 216-0001, Japan; and the § Human Gene Sciences Center, Tokyo Medical and Dental
University, Bunkyo-ku, Tokyo 113, Japan
![]() |
Abstract |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
We investigated the role of antigen-presenting cells in early interferon (IFN)- production in
normal and recombinase activating gene 2-deficient (Rag-2
/
) mice in response to Listeria
monocytogenes (LM) infection and interleukin (IL)-12 administration. Levels of serum IFN-
in
Rag-2
/
mice were comparable to those of normal mice upon either LM infection or IL-12
injection. Depletion of natural killer (NK) cells by administration of anti-asialoGM1 antibodies
had little effect on IFN-
levels in the sera of Rag-2
/
mice after LM infection or IL-12 injection. Incubation of splenocytes from NK cell-depleted Rag-2
/
mice with LM resulted in the
production of IFN-
that was completely blocked by addition of anti-IL-12 antibodies. Both
dendritic cells (DCs) and monocytes purified from splenocytes were capable of producing IFN-
when cultured in the presence of IL-12. Intracellular immunofluorescence analysis confirmed
the IFN-
production from DCs. It was further shown that IFN-
was produced predominantly by CD8
+ lymphoid DCs rather than CD8
myeloid DCs. Collectively, our data indicated that DCs are potent in producing IFN-
in response to IL-12 produced by bacterial infection and play an important role in innate immunity and subsequent T helper cell type 1 development in vivo.
![]() |
Introduction |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Dendritic cells (DCs) are bone marrow (BM)-derived professional APCs. Peripheral DCs are characterized by high capability for antigen capture and processing, migration to lymphoid organs, and expression of various costimulatory molecules for antigen-specific lymphocyte activation. Cytokine secretion by DCs initiates and enhances both innate and acquired immunity (1).
Activation of macrophages and DCs by infectious agents
leads to secretion of IL-12, which subsequently induces
IFN- production by NK cells and directs Th1 development. IFN-
, in turn, acts on monocytes to augment IL-12
secretion and to produce nitric oxide that eradicates infected
microbes (2, 3). Thus, IL-12 and IFN-
comprise a positive
feedback system, which is probably required for optimal
production of IL-12 in vivo (4, 5). Studies using neutralizing Abs against IFN-
and mice deficient for IL-12 or IFN-
have confirmed the importance of these cytokines for innate
immunity and Th1 development for controlling intracellular pathogens (6).
It was generally assumed that the only cells producing
IFN- in response to IL-12 are NK and T cells. However,
recent studies have shown that IFN-
is also produced by
peritoneal macrophages in response to IL-12 and by BM-derived macrophages in response to a combination of IL-12
and IL-18, suggesting the presence of an autocrine activation pathway (12, 13).
In the study presented here, we examined IFN- production pathways in NK cell-depleted recombinase activating
gene 2-deficient (Rag-2
/
) mice upon Listeria monocytogenes
(LM) infection or IL-12 administration. We found that the
levels of IFN-
produced in the sera of these mice were unaltered as compared with those of Rag-2
/
mice with NK
cells, suggesting an important role for a non-T, -B, and/or
-NK cell type(s) in producing IFN-
in vivo. We show here
that purified DCs were capable of producing significant
amounts of IFN-
in response to IL-12. Among DCs,
CD8
+ lymphoid DCs are the major producers of IFN-
.
Thus, DCs produce IFN-
in an autocrine manner by responding to the IL-12 they produce upon bacterial infection,
and such autocrine production of IFN-
likely plays an important role in both innate and acquired immunity in vivo.
![]() |
Materials and Methods |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Mice.
B10.D2 and C57BL/6 mice were purchased from Sankyo Labo Service Co. Inc. (Japan). B10.D2-Rag-2Listeria monocytogenes.
Listeria monocytogenes EGD strain (LM) was provided by M. Mitsuyama of Kyoto University (Kyoto, Japan). The bacteria had been passed through C57BL/6 mice and colonies were obtained from the spleens of infected mice on agar plates with trypto-soy broth (Eiken Chemical Co., Japan). Bacteria were then grown in trypto-soy broth overnight at 37°C. Aliquots of bacteria suspension were stored atCell Preparation.
Splenocytes were prepared by homogenizing collagenase-treated spleens in all experiments. DCs were prepared from spleens as previously described (17). In brief, collagenase-treated spleens (Collagenase D; Boehringer Mannheim) were homogenized and suspended in a dense BSA solution (P = 1.080), overlaid with 1 ml of RPMI medium, and centrifuged in a swing bucket rotor at 9,500 g for 10 min at 4°C. DCs and monocytes at the interface were collected, washed, and allowed to adhere to plastic dishes for 2 h. Cells were incubated for an additional 18 h to allow DCs to detach from the plastic dishes. Nonadherent cells containing DCs were then collected and contaminated B cells were further excluded by anti-mouse Ig(H+L)-beads (Perseptive Biosystems) using a MACS magnet (Miltenyi Biotech). After removing DCs, adherent macrophages were detached from the plastic dishes by a cell scraper (Sumitomo Bakelite Co. Ltd., Japan). NK cells were enriched by a combination of PK136-biotin (anti-NK1.1) and Streptavidin-MicroBeads (Miltenyi Biotech). These fractions were stained with appropriate mAbs and were further purified by cell sorting on a FACS VantageTM (Becton Dickinson).Antibodies and Flow Cytometric Analysis.
The following mAbs were purchased from PharMingen: 145-2C11-FITC and 145-2C11-PE (anti-CD3Cytokine Assays.
To induce IFN-Intracellular Immunofluorescence Analysis.
Immunofluorescence staining of intracellular IFN- ![]() |
Results |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Several studies have demonstrated that IFN- produced by NK as well as Th1 cells is a crucial cytokine for
limiting and clearing infectious intracellular agents such as
protozoan and bacterial pathogens (6, 19). To examine
the role of NK cells in the early production of IFN-
, we
injected polyclonal
ASGM1 Abs into B10.D2 or B10.D2-
Rag-2
/
mice to deplete NK cells as previously demonstrated (23). Consistent with previous studies, NK cells were
absent in the spleen of both B10.D2 and B10.D2-Rag-2
/
mice 3 d after administration of 300 µg
ASGM1 Ab (Fig.
1 A). These mice were then injected with 2 × 106 LM or
0.5 µg IL-12, and serum IFN-
levels were examined after 48 and 24 h, respectively. As shown in Fig. 1 B, IFN-
was
detected in the sera of NK cell-depleted B10.D2 mice at a
level comparable to those in untreated B10.D2 mice upon
LM infection (Fig. 1 B, top). As both T and B cells (24) are
able to produce IFN-
, we performed the same experiment with B10.D2-Rag-2
/
mice lacking both T and B
cells. To our surprise, comparable levels of IFN-
were induced in NK cell-depleted B10.D2-Rag-2
/
mice and in
untreated B10.D2-Rag-2
/
mice (Fig. 1 B, top).
|
Because IL-12 is important in inducing IFN-, we also
injected recombinant IL-12 into these mice and observed
IFN-
production in the sera independent of NK cell depletion (Fig. 1 B, top). IFN-
was not detected in the sera of
mice injected with PBS or
ASGM1 alone. These data suggest that the contribution of NK cells to early IFN-
production in response to LM infection or IL-12 administration
is minimal. We further examined C57BL/6-
c
/
(Y)Rag-2
/
mice lacking T, B, and NK cells, as well as NOD/LtSz-scid/
scid mice lacking T and B cells and having functional defects
in NK cells and monocytes/macrophages (16). After 24 h
of IL-12 administration, only a small amount of serum
IFN-
was detected in C57BL/6-
c
/
(Y)Rag-2
/
mice,
whereas substantial amounts of IFN-
were produced by
NOD/LtSz-scid/scid mice. IFN-
production in NOD/
LtSz-scid/scid mice was also unaffected by pretreatment
with
ASGM1 Ab (Fig. 1 B, bottom, and data not shown).
To identify the IFN--producing cells in
ASGM1-treated Rag-2
/
mice, splenocytes were prepared from mice
treated with
ASGM1 and infected LM in vitro. As shown
in Fig. 1 C, IFN-
was produced by Rag-2
/
splenocytes
in the absence of NK cells, and the production of IFN-
was
completely blocked by the addition of anti-IL-12 Ab, indicating that IL-12 plays a critical role in IFN-
production upon LM infection. These results further indicate the presence of IFN-
-producing cells other than T, B, and NK
cells. In contrast, amounts of IFN-
produced by C57BL/
6-
c
/
(Y)Rag-2
/
splenocytes were 1-5% of those from
NK-depleted Rag-2
/
splenocytes upon either Listeria infection or IL-12 administration, suggesting that IFN-
production is impaired in C57BL/6-
c
/
(Y)Rag-2
/
mice.
To further identify IFN--
producing cells, DCs as well as macrophages and NK cells
were freshly isolated from collagenase-treated spleen cells of
unprimed mice by cell sorting. Highly purified CD11c+ I-A+,
Mac1+F4/80+, and CD3-NK1.1+ cells were used as DCs,
macrophages, and NK cells, respectively (Fig. 2 A and data
not shown). These cells were cultured for 3 d in the presence
of 1 ng/ml IL-12 in vitro. As shown in Fig. 2 B, significant
amounts of IFN-
were detected in the culture supernatants
of DCs and macrophages. The amounts of IFN-
from DCs
and macrophages were significantly higher than those from NK cells. DCs cultured in the absence of IL-12 produced
IFN-
to a certain level, probably due to the cross-linking of
surface MHC class II molecules by the use of anti-I-A mAb
for DC preparation (25). Consistent with this interpretation,
DCs purified using anti-CD86 mAb (26) instead of anti-I-A
mAb did not produce IFN-
without IL-12 (see Fig. 3 B).
|
|
There are two different types of DCs
in the spleen of an adult mouse (27). They differ in surface phenotypes (CD8DEC-205
CD11b+ versus CD8
+
DEC-205+CD11b
), origin (myeloid versus lymphoid), requirement of cytokines for their development (GM-CSF
versus IL-3), and biological function. To this end, we examined IFN-
production from DC subpopulations. CD8
DCs (myeloid DCs) and CD8
+ DCs (lymphoid DCs) were
isolated by cell sorting and cultured with 1 ng/ml IL-12 for
3 d. As shown in Fig. 3, CD8
+ DCs were found to produce an approximately fivefold higher level of IFN-
than
do CD8
DCs, indicating that CD8
+ lymphoid DCs are
the major IFN-
producers in response to IL-12 stimulation.
Immunofluorescence microscopy was conducted to directly detect the
expression of IFN- protein in DCs. Purified CD11c+
CD86+ splenic DCs were cultured in the presence of IL-12
for 3 d, fixed on coverslips, and subjected to intracellular immunofluorescence microscopic analysis. As shown in Fig. 4,
IFN-
proteins were clearly detected in the cytoplasm of
CD11c+ DCs (Fig. 4, A and D), whereas staining was undetectable with the control rabbit serum (Fig. 4, C and F).
Consistent with a previous study (31), expression of IL-12Rs
was readily observed on the cell surface of DCs (Fig. 4, B
and E). IFN-
was not detected in freshly isolated DCs but
was detected in splenic macrophages upon IL-12 stimulation
by immunofluorescence microscopy (data not shown).
|
![]() |
Discussion |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
We presented here evidence that NK cells play a small
role in the production of IFN- at early stages of LM infection or IL-12 administration, and that DCs and macrophages produce IFN-
. Among DC subpopulations, CD8
+
lymphoid DCs are major producers of IFN-
in response
to IL-12. Recent studies have also reported the ability of
macrophages to produce IFN-
(12, 13). Amounts of IFN-
produced by DCs and macrophages were substantially
larger than the amount produced by NK cells.
It has long been assumed that IL-12 is initially produced by
macrophages in response to various intracellular pathogens
and later by DCs (32, 33), based on the observations that DCs produce IL-12 through ligation of CD40 on DCs by CD40L
on activated T cells, or through cross-linking of MHC class II
molecules by the TCR (25, 34). However, it has been shown
recently that phagocytosis of microparticle-adsorbed proteins
stimulates DCs to synthesize IL-12 without interacting with
T cells (35), and that DCs but not macrophages produce
IL-12 in vivo in microbial infection such as Toxoplasma gondii
(36). Furthermore, accumulating evidence has indicated that
resting macrophages are unable to produce IL-12 in response
to bacteria or microbial products such as LPS without prior
activation by certain cytokines such as IFN- (4, 37, 38).
In this paper we showed that DCs are able to produce
IFN- upon IL-12 stimulation. Because DCs produce IL-12
upon phagocytosis and microbial infection, and IL-12 in turn
augments the production of IL-12 itself from DCs (31, 35,
36), it is likely that DCs produce IL-12 and IFN-
by an
autocrine manner once they have been triggered by microbial infection. The fact that the addition of anti-IL-12 Ab
completely blocked the IFN-
production by NK cell-
depleted Rag-2
/
splenocytes upon LM infection supports
this notion. In addition to IL-12, IL-18 and IL-1
are also
likely to be involved in augmenting IFN-
production
from DCs in vivo, as observed in T and NK cells (39, 40).
Our results on C57BL/6-c
/
(Y)Rag-2
/
mice are consistent with a recent paper by Andersson et al. that reports
that
c
/
(Y)Rag-2
/
mice produce minimal amount of
IFN-
(41). Since these mice lack NK cells as well as T and
B cells, it was concluded that NK cells are the major producers of IFN-
. Flow cytometric analysis showed the presence
of normal numbers of DCs and macrophages in the spleens
of C57BL/6-
c
/
(Y)Rag-2
/
mice (Ohteki, T., and S. Koyasu, unpublished results). It is likely that APCs in the
c
/
(Y)Rag-2
/
mice have some functional rather than
developmental defects that remain to be examined.
It is likely that the IFN- derived from DCs plays a key
role in priming and activating macrophages to produce
IL-12 in response to intracellular pathogens. DC-derived
IFN-
, together with IL-12, may also be important in upregulation of surface molecules on DCs such as MHC class
II. Once IL-12 and IFN-
are produced by DCs, a positive
feedback pathway(s) would be activated between DCs and
macrophages even in the absence of NK cell-derived IFN-
. Macrophages then secrete IFN-
in response to IL-12 or a
combination of IL-12 and IL-18 (12, 13), which also activates macrophages in an autocrine manner to produce nitric oxide. In microbial infection such pathways would be
quicker than the pathway through NK cell-derived IFN-
,
and thus important, although not sufficient, for an early stage of innate immune response.
DCs are divided into at least two subpopulations by origins, surface molecules, and the requirement of cytokines for
their development (27). One subpopulation is myeloid
DCs without CD8 expression, and the second is lymphoid
DCs expressing CD8
. It has been shown that CD8
+ lymphoid DCs primarily produce IL-12 in vivo in intracellular protozoan infection (36). Given that the CD8
+ DCs produce IFN-
in response to IL-12 (Fig. 3) and predominantly localized in the T cell area of the spleen (30), lymphoid
CD8
+ DCs rather than myeloid CD8
DCs are probably
the most efficient initiators for innate immune response
upon infection of intracellular microorganisms, as well as the
directors of subsequent Th1 differentiation in vivo.
![]() |
Footnotes |
---|
Address correspondence to Shigeo Koyasu, Department of Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Phone: 81-3-3353-1746; Fax: 81-3-5361-7658; E-mail: koyasu{at}sun.microb.med.keio.ac.jp
Received for publication 1 February 1999 and in revised form 19 April 1999.
We thank Dr. Mitsuyama for providing LM, and Drs. N. Hozumi and J. Hata for providing NOD/ LtSz-scid/scid mice. We also thank A. Sakurai for excellent animal care.
This work was supported by a grant from the KANAE Foundation for Life & Socio-Medical Science to T. Ohteki, a Grant-in-Aid for Scientific Research on Priority Areas from the Ministry of Education, Science, Sports and Culture of Japan (10153261), a National Grant-in-Aid for the Establishment of a High-Tech Research Center in a Private University, a Keio University Special Grant-in-Aid for Innovative Collaborative Research Projects, and a grant from the Japan Society for the Promotion of Science (JSPS-RFTF 97L00701) to S. Koyasu. K. Suzue is supported by a Research Fellowship of the Japan Society for the Promotion of Science for Young Scientists.
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1. | Banchereau, J., and R.M. Steinman. 1998. Dendritic cells and the control of immunity. Nature. 392: 245-252 [Medline]. |
2. | Trinchieri, G.. 1995. Interleukin-12: a proinflammatory cytokine with immunoregulatory functions that bridge innate resistance and antigen-specific adaptive immunity. Annu. Rev. Immunol. 13: 251-276 [Medline]. |
3. | MacMicking, J., Q.-W. Xie, and C. Nathan. 1997. Nitric oxide and macrophage function. Annu. Rev. Immunol. 15: 323-350 [Medline]. |
4. |
Ma, X.,
J.M. Chow,
G. Gri,
F. Carra,
S.F. Gerosa,
R. Wolf,
R. Dzialo, and
G. Trinchieri.
1996.
The interleukin 12 p40
gene promoter is primed by interferon ![]() |
5. |
Kubin, M.,
J.M. Chow, and
G. Trinchieri.
1994.
Differential
regulation of interleukin-12 (IL-12), tumor necrosis factor-![]() ![]() |
6. |
Buchmeier, N.A., and
R.D. Schreiber.
1985.
Requirement
of endogenous interferon-![]() |
7. |
Harty, J.T., and
M.J. Bevan.
1995.
Specific immunity to Listeria monocytogenes in the absence of IFN![]() |
8. |
Dai, W.J.,
W. Bartens,
G. Kohler,
M. Hufnagel,
M. Kopf, and
F. Brombacher.
1997.
Impaired macrophage listericidal
and cytokine activities are responsible for the rapid death of
Listeria monocytogenes-infected IFN-![]() |
9. |
Magram, J.,
S.E. Connaughton,
R.R. Warrier,
D.M. Carvajal,
C.Y. Wu,
J. Ferrante,
C. Stewart,
U. Sarmiento,
D.A. Faherty, and
M.K. Gately.
1996.
IL-12-deficient mice are
defective in IFN ![]() |
10. | Magram, J., J. Sfarra, S. Connaughton, D.A. Faherty, R. Warrier, D. Carvajal, C.Y. Wu, U. Sarmiento, and M.K. Gately. 1996. IL-12 deficient mice are defective but not devoid of type 1 cytokine responses. Ann. NY Acad. Sci. 795: 60-70 [Abstract]. |
11. |
Wakil, A.E.,
Z.-E. Wang,
J.C. Ryan,
D.J. Fowell, and
R.M. Locksley.
1998.
Interferon ![]() |
12. |
Puddu, P.,
L. Fantuzzi,
P. Borghi,
V. Barbara,
G. Rainaldi,
E. Guillemard,
W. Malorni,
P. Nicaise,
S.F. Wolf,
F. Belardelli, and
S. Gessani.
1997.
IL-12 induces IFN-![]() |
13. |
Munder, M.,
M. Mallo,
K. Eichmann, and
M. Modolell.
1998.
Murine macrophages secrete interferon ![]() |
14. | Shinkai, Y., G. Rathbun, K.-P. Lam, E.M. Oltz, V. Stewart, M. Mendelsohn, J. Charron, M. Datta, F. Young, A.M. Stall, and F.W. Alt. 1992. RAG-2-deficient mice lack mature lymphocytes owing to inability to initiate V(D)J rearrangement. Cell. 68: 855-867 [Medline]. |
15. |
Ohbo, K.,
T. Suda,
M. Hashiyama,
A. Mantani,
M. Ikebe,
K. Miyakawa,
M. Moriyama,
M. Nakamura,
M. Katuki,
K. Takahashi, et al
.
1996.
Modulation of hematopoiesis in mice
with a truncated mutant of the interleukin-2 receptor ![]() |
16. |
Shultz, L.D.,
P.A. Schweitzer,
S.W. Christianson,
B. Gott,
I.B. Schweitzer,
B. Tennent,
S. McKenna,
L. Mobraaten,
T.V. Rajan,
D.L. Greiner, and
E.H. Leiter.
1995.
Multiple
defects in innate and adaptive immunologic function in
NOD/LtSz-scid mice.
J. Immunol.
154:
180-191
|
17. | Steinman, R.M., W.C. Van Voorhis, and D.M. Spalding. 1986. Dendritic cells. In Handbook of Experimental Immunology. D.W. Weir, L.A. Herzenberg, C. Blackwell, and L.A. Herzenberg, editors. Blackwell, London. 49.1-49.9. |
18. |
Rovere, P.,
V.S. Zimmermann,
F. Forquet,
D. Demandolx,
J. Trucy,
P. Ricciardi-Castagnoli, and
J. Davoust.
1998.
Dendritic cell maturation and antigen presentation in the absence
of invariant chain.
Proc. Natl. Acad. Sci. USA.
95:
1067-1072
|
19. | Bancroft, G.J., R.D. Schreiber, and E.R. Unanue. 1991. Natural immunity: a T cell independent pathway of macrophage activation, defined in the scid mouse. Immunol. Rev. 124: 5-24 [Medline]. |
20. | Laskay, T., R. Rollinghoff, and W. Solbach. 1993. Natural killer cells participate in the early defense against Leishmania major infection in mice. Eur. J. Immunol. 23: 2237-2241 [Medline]. |
21. | Scharton, T.M., and P. Scott. 1993. Natural killer cells are a source of interferon that drives differentiation of CD4+ T cell subsets and induces early resistance to Leishmania major in mice. J. Exp. Med. 178: 567-577 [Abstract]. |
22. |
Denkers, E.Y.,
R.T. Gazzinelli,
D. Martin, and
A. Sher.
1993.
Emergence of NK1.1+ cells as effectors of IFN-![]() |
23. | Yu, Y.Y., V. Kummar, and M. Bennett. 1992. Murine natural killer and marrow graft rejection. Annu. Rev. Immunol. 10: 189-213 [Medline]. |
24. |
Yoshimoto, T.,
H. Okamura,
Y.I. Tagawa,
Y. Iwakura, and
K. Nakanishi.
1997.
Interleukin 18 together with interleukin
12 inhibits IgE production by induction of interferon-gamma
production from activated B cells.
Proc. Natl. Acad. Sci. USA.
94:
3948-3953
|
25. | Koch, F., U. Stanzl, P. Jennewein, K. Janke, C. Heufler, E. Kampgen, N. Romani, and G. Schuler. 1996. High level IL-12 production by murine dendritic cells: upregulation via MHC class II and CD40 molecules and downregulation by IL-4 and IL-10. J. Exp. Med. 184: 741-747 [Abstract]. |
26. | Inaba, K., M. Witmer-Pack, M. Inaba, S. Hathcock, H. Sakuta, M. Azuma, H. Yagita, K. Okumura, P.S. Linsley, S. Ikehara, et al . 1994. The tissue distribution of the B7-2 costimulator in mice: abundant expression on dendritic cells in situ and during maturation in vitro. J. Exp. Med. 180: 1849-1860 [Abstract]. |
27. | Vremec, D., M. Zorbas, R. Scolly, D.J. Saunders, C.F. Ardavin, L. Wu, and K. Shortman. 1992. The surface phenotype of dendritic cells purified from mouse thymus and spleen: investigation of the CD8 expression by a subpopulation of dendritic cells. J. Exp. Med. 176: 47-58 [Abstract]. |
28. | Wu, L., C.-L. Li, and K. Shortman. 1996. Thymic dendritic cell precursors: relationship to the T-lymphocyte lineage and phenotype of the dendritic cell progeny. J. Exp. Med. 184: 903-911 [Abstract]. |
29. | Vremec, D., and K. Shortman. 1997. Dendritic cell subtypes in mouse lymphoid organs: cross-correlation of surface markers, changes with incubation, and differences among thymus, spleen, and lymph nodes. J. Immunol. 159: 565-573 [Abstract]. |
30. | Steinman, R.M., M. Pack, and K. Inaba. 1997. Dendritic cells in the T-cell areas of lymphoid organs. Immunol. Rev. 156: 25-37 [Medline]. |
31. |
Grohmann, U.,
M. Belladonna,
R. Bianchi,
C. Orabona,
E. Ayroldi,
M. Fioretti, and
P. Puccetti.
1998.
IL-12 acts directly on DC to promote nuclear localization of NF-![]() |
32. |
Locksley, R.M..
1993.
Interleukin 12 in host defense against microbial pathogens.
Proc. Natl. Acad. Sci. USA.
90:
5879-5880
|
33. | Hsieh, C.-S., S.E. Macatonia, C.S. Tripp, S.F. Wolf, A. O'Garra, and K.M. Murphy. 1993. Development of TH1 CD4+ T cells through IL-12 produced by Listeria-induced macrophages. Science. 260: 547-549 [Medline]. |
34. | Cella, M., D. Scheidegger, K. Palmer-Lehmann, P. Lane, A. Lanzavecchia, and G. Alber. 1996. Ligation of CD40 on dendritic cells triggers production of high levels of interleukin-12 and enhances T cell stimulatory capacity: T-T help via APC activation. J. Exp. Med. 184: 747-752 [Abstract]. |
35. |
Sheisher, C.,
M. Mehlig,
H.-P. Dienes, and
K. Reske.
1995.
Uptake of microparticle-adsorbed protein antigen by bone
marrow-derived dendritic cells results in up-regulation of interleukin-1![]() |
36. |
Sousa, C.R.,
S. Hieny,
T. Scharton-Kersten,
D. Jankovic,
H. Charest,
R.N. Germain, and
A. Sher.
1997.
In vivo microbial stimulation induces rapid CD40 ligand-independent
production of interleukin 12 by dendritic cells and their redistribution to T cell areas.
J. Exp. Med.
186:
1819-1829
|
37. |
Flesch, I.E.,
J.H. Hess,
S. Huang,
M. Aguet,
J. Rothe,
H. Bluethmann, and
S.H. Kaufmann.
1995.
Early interleukin 12 production by macrophages in response to mycobacterial infection depends on interferon ![]() ![]() |
38. | Skeen, M.J., M.A. Miller, T.M. Shinnick, and H.K. Ziegler. 1996. Regulation of murine macrophage IL-12 production. Activation of macrophages in vivo, restimulation in vitro, and modulation by other cytokines. J. Immunol. 156: 1196-1206 [Abstract]. |
39. |
Okamura, H.,
H. Tsutsi,
T. Komatsu,
M. Yutsudo,
A. Hakura,
T. Tanimoto,
K. Torigoe,
T. Okura,
Y. Nukada,
K. Hattori, et al
.
1995.
Cloning of a new cytokine that induces
IFN-![]() |
40. |
Hunter, C.A.,
R. Chizzonite, and
J.S. Remington.
1995.
IL-1![]() ![]() ![]() |
41. |
Andersson, A.,
W.J. Dai,
J.P. Di Santo, and
F. Brombacher.
1998.
Early IFN-![]() |